DCP Series X.25 Packet Switched Communications Software (PSCS ...

Product Information
Announcement
New Release Revision Update New Mail Code
Title:
DCP Series X.25 Packet Switched Communications Software (PSCS) Configuration and Operations Guide
Level 5R2D
This Product Information Announcement announces the release and availability of the DCP Series X.25 Packet
Switched Communications Software (PSCS) Configuration and Operations Guide (7831 5470–200).
The Unisys DCP Series X.25 PSCS program product provides added functions for Telcon software on a Unisys
Distributed Communications Processor (DCP). X.25 PSCS provides DCPs with access to packet networks that use
the X.25 protocol. These include the Defense Data Network (DDN), many public data networks (PDNs), and private
packet networks. It supports communications with other devices using the Distributed Communications Architecture
(DCA), System Network Architecture (SNA), transmission control protocol/internet protocol (TCP/IP), and open
systems interconnection (OSI) protocols.
In addition, X.25 PSCS provides the DCE Network feature that enables Telcon networks to function as private
packet networks. This feature enables directly attached DTEs to use the X.25 protocol to access the Telcon
network for communications with other DTEs.
This document is a full revision and should totally replace earlier revisions and updates.
To order additional copies of this document:
• United States customers, call Unisys Direct at 1-800-448-1424.
• All other customers, contact your Unisys Sales Office.
• Unisys personnel, use the Electronic Literature Ordering (ELO) system.
Announcement only:
MBWA, MBZ, MU59, MX3,
MX5, MX6, MX7, MX8, MY5
Announcement and attachments:
AFO1
System: DCP Series
Release: Level 5R2D
December 1994
Part number: 7831 5470–200

DCP Series
X.25 Packet Switched
Communications
Software (PSCS)
Configuration and
Operations
Guide
Copyright© 1994 Unisys Corporation.
All rights reserved.
Unisys is a registered trademark of Unisys Corporation.
5R2D December 1994
Printed in U S America
Priced Item 7831 5470–200

NO WARRANTIES OF ANY NATURE ARE EXTENDED BY THE DOCUMENT. Any product
and related material disclosed herein are only furnished pursuant and subject to the terms and
conditions of a duly executed agreement to purchase or lease equipment or to license
software. The only warranties made by Unisys Corporation, if any, with respect to the products
described in this document are set forth in such agreement. Unisys Corporation cannot
accept any financial or other responsibility that may be the result of your use of the
information in this document or software material, including direct, indirect, special, or
consequential damages.
You should be very careful to ensure that the use of this information and/or software material
complies with the laws, rules, and regulations of the jurisdictions with respect to which it is
used.
The information contained herein is subject to change without notice. Revisions may be issued
to advise of such changes and/or additions.
Correspondence regarding this publication should be forwarded to Unisys Corporation by
addressing remarks to Communication Systems Product Information, Salt Lake City
Publications, MS B2B07, 322 North 2200 West, Salt Lake City, UT 84116-2979, U.S.A.
Telenet is a registered trademark of General Telephone and Electronics Corporation.
UNISCOPE is a registered trademark of Unisys Corporation.
UNIX is a registered trademark of X/Open Company Limited.

Contents
About This Guide ............................................. xv
Section 1. Introduction
1.1. X.25 PSCS Product Overview ..................1–3
1.1.1. DCE Network Feature .......................1–3
1.1.2. ILM-20 Support ...........................1–4
1.1.3. Idle Trunk Circuit Handling ....................1–5
1.1.4. CNMS Interface ...........................1–5
1.1.5. Packet Network Access ......................1–5
1.1.6. Support for Standard and Proprietary Protocols .....1–6
1.1.7. Public Data Networks Supported ................1–7
1.1.8. Special Network Certification ..................1–7
1.1.9. Special Capabilities .........................1–8
1.1.10. DTE Routing and Routing Precedence ............1–9
1.1.11. Minimizing Packet Layer Services (PLS) DTEs .......1–9
1.1.12. Message Tracing .........................1–10
1.1.13. 1988 ITU/TSS (CCITT) Compliance .............1–10
1.1.14. Coded Character Sets ......................1–10
1.1.15. Dynamic Line Switching .....................1–10
1.2. X.25 PSCS Limitations ......................1–11
1.3. X.25 PSCS Restrictions .....................1–12
1.4. DCE Network Limitations ....................1–13
1.5. DCP Loading Over X.25 Networks .............1–14
1.6. Migration Issues ...........................1–15
1.6.1. X25ROUTE Statement ......................1–15
1.6.2. Level 4 Program Definition for SNA/net ..........1–17
7831 5470–200 v

Contents
vi
Section 2. Configuring Standard X.25 PSCS Capabilities
2.1. Configuring Basic Connections to Networks .......2–3
2.1.1. Configuring a Connection to a PDN ..............2–3
2.1.2. Configuring a Connection to the DDN .............2–5
2.1.3. Configuring a Multilink Connection ...............2–7
2.2. Defining DTEs .............................2–9
2.2.1. Configuring a DCP as a DTE ..................2–10
2.2.2. Configuring a UTS 4000 Cluster Controller
as a DTE...............................2–14
2.2.3. Configuring the Packet Layer Services (PLS)
Interface as a DTE ........................2–17
2.2.4. Configuring a U Series Running DNS as a DTE .....2–19
2.2.5. Configuring a U Series or IS-PC (Running TS/TN)
as a DTE...............................2–21
2.2.6. Configuring a DTE Running SNA Protocols ........2–23
2.2.7. Configuring DTEs Using Permanent Virtual Circuits . . . 2–25
2.3. Configuring an X.29 PAD ....................2–27
2.4. Configuring an X.28/PAD ....................2–29
2.5. Configuring Special X.25 PSCS Capabilities ......2–33
2.5.1. Configuring Packet Size .....................2–33
2.5.2. Configuring Packet Level Window Size ...........2–33
2.5.3. Configuring Frame Size .....................2–34
2.5.4. Configuring a Frame Level Window .............2–35
2.5.5. Configuring Permanent Virtual Circuits ...........2–36
2.5.6. Configuring the CALLED and CALLING Options .....2–37
2.5.7. Configuring Partial DTE Addresses .............2–38
2.5.8. Configuring Incoming Call Routing Precedence .....2–41
Section 3. Configuring a DCE Network
3.1. Planning the Network ........................3–3
3.1.1. Drawing a Network Map .....................3–3
3.1.2. Rules for Creating Network Addresses ............3–5
3.1.3. Selecting Statements .......................3–8
3.2. Configuring the DCE Network .................3–10
3.2.1. Configuring a One-Node DCE Network ...........3–10
3.2.2. Adding a Node and DTEs to a DCE Network .......3–13
3.2.3. Configuring an Internal DTE ..................3–16
3.2.4. Configuring an Internal DTE for U Series or IS-PC
DTEs Running with the TS/TN Protocol ..........3–20
3.2.5. Configuring an X.75 Interface to Another Network . . . 3–24
7831 5470–200

Contents
3.3. Configuring Special DCE Network Capabilities ....3–27
3.3.1. Configuring a Closed User Group ..............3–27
3.3.2. Configuring Priority Virtual Circuits ..............3–30
3.3.3. Configuring Reverse Charging .................3–31
3.3.4. Configuring Flow Control Negotiation ............3–32
3.3.5. Configuring DTE Hunt Groups .................3–33
3.3.6. Configuring DTE Subaddresses ................3–35
3.3.7. Configuring an ILM-20 Connection to a DTE .......3–37
3.3.8. Configuring a Multilink Protocol Connection ........3–38
Section 4. Configuration Examples
4.1. DCP-to-DCP Trunk ..........................4–3
4.2. DCP-to-DCP Multilink Trunk ...................4–8
4.3. DCP-to-DCP Mixed Trunk ....................4–14
4.4. DCP-to-UTS 4000 Cluster Controller ...........4–19
4.5. DCP-to-U Series or IS-PC (TS/TN) ..............4–24
4.6. X.28/PAD ...............................4–29
4.7. X.29 PAD with Nonconfigured DTEs ............4–33
4.8. X.29 PAD with Configured DTEs and X25ROUTE
Statement ............................. 4–38
4.9. DCP-to-Remote Host Using PLS ...............4–43
4.10. Two-Node DCE Network .....................4–48
Section 5. Using Network Management Services (NMS)
5.1. NMS Command Authority Levels ...............5–3
5.2. DOWN — Deactivating a Facility ................5–4
5.3. LIST — Displaying Line Activity ................5–6
5.4. RECORD — Controlling DCE Network Statistics
Gathering ................................5–9
5.5. STAT — Displaying Status ...................5–11
5.5.1. STAT LINE Display ........................5–13
5.5.2. STAT PDTE Display ........................5–15
5.5.3. STAT PTRK Display ........................5–17
7831 5470–200 vii

Contents
viii
5.6. SWITCH — Rerouting Call Packets .............5–19
5.7. TRAC — Message Tracing ...................5–21
5.7.1. TRAC SNAP X25 ..........................5–21
5.7.2. TRAC SNAP DCEF .........................5–27
5.8. UP — Activating a Facility ...................5–29
Section 6. Using X.25 PSCS Configuration Statements
6.1. CLSTR — Defining UTS Terminal Clusters .........6–4
6.2. DTE — Defining Data Terminal Equipment ........6–5
6.2.1. DTEs on PDNs, the DDN, or Private Networks .......6–6
6.2.2. DTEs on DCE Networks .....................6–11
6.3. DTETYPE — Defining DTE Communication
Attributes ................................6–15
6.3.1. DTETYPEs for Standard Packet Networks .........6–16
6.3.2. DTETYPEs for DCE Networks .................6–23
6.4. EU — Defining X.25 PSCS End Users ...........6–25
6.4.1. EUs for X.28/PAD End Users .................6–25
6.4.2. EUs for PLS End Users .....................6–30
6.4.3. EUs for DCE Network ......................6–32
6.5. LCLASS — Defining Line Characteristics ........6–34
6.5.1. LCLASS For Standard Communications Lines ......6–34
6.5.2. LCLASS For ILM-20 Lines ....................6–35
6.6. LINE — Defining Physical Communications Lines . . 6–36
6.7. PDNGRP — Defining a Network Connection ......6–38
6.7.1. PDNGRPs for PDNs and Private Packet Networks . . . 6–39
6.7.2. PDNGRPs for the DDN ......................6–43
6.7.3. PDNGRPs for DCE Networks .................6–47
6.8. PDNPAD — Defining Operational Parameters
for a PAD ................................6–50
6.9. TERM — Defining a Terminal .................6–58
6.9.1. Terminals Using the UTS 4000 Cluster Controller . . . 6–58
6.9.2. Terminals Using the X.29 PAD ................6–59
7831 5470–200

Contents
6.10. X25DEF — Defining Network Characteristics .....6–61
6.11. X25NET — Defining DCE Network Routes ........6–73
6.12. X25ROUTE — Specifying Routing Precedence ....6–75
Section 7. X.25 PSCS Troubleshooting
7.1. Troubleshooting Overview ....................7–2
7.2. Verifying Line Operation .....................7–3
7.2.1. Verifying General Line Operation ................7–3
Determining If X.25 PSCS Installation Failed ......7–4
Determining If X.25 PSCS Initialization Failed ......7–5
Determining If Hardware/DCP System Resources
Failed ................................7–6
7.2.2. Verifying Specific Line Operation ................7–8
Physical Layer Connection ..................7–9
Link Layer Connection .....................7–9
7.3. Verifying Virtual Circuit Connections ...........7–11
7.3.1. Using Data Session or Service Operation to Verify
Connections .............................7–11
7.3.2. Using NMS Commands to Verify Connections ......7–11
7.3.3. Connection Troubleshooting Actions ............7–13
Generating Telcon CENLOG Reports ..........7–13
Generating Layer 3/4 Platform Interface User
Reports ..............................7–14
Using Message Tracing ...................7–14
7.4. Verifying Message Data Transfer Performance ....7–15
7.4.1. Identifying External Facilities and Interfaces That
May Affect Data Transfer Performance ...........7–15
Determining Adequate Virtual Circuit Connection
Resources ............................7–15
Determining Whether Telcon or Host Interface
Resources Affect Data Transfer .............7–16
Determining Adequate DCP/OS Resources ......7–17
7.4.2. Determining Areas Within X.25 PSCS That Affect
Data Transfer ............................7–18
Packet Level Characteristics ................7–18
Incompatible Flow Control Values ...........7–18
Facility Constraints ....................7–19
Link Level Characteristics ..................7–19
Incompatible Frame Control Values .........7–19
Subscription Parameters ................7–20
Physical Line Characteristics ...............7–20
7831 5470–200 ix

Contents
x
Appendix A. X.25 PSCS Reserved Words
Appendix B. X.25 PSCS Outgoing Call Routing Concepts
Appendix C. NMS TRAC Command Trace File Formats
C.1. SNAP=X25 Parameter Option Format ............C–2
C.2. SNAP=DCEF Parameter Option Format ...........C–4
7831 5470–200

Figures
2–1. DCP Connection Configured to a PDN ............................2–3
2–2. DCP Connection Configured to the DDN ..........................2–5
2–3. DCP Connection Configured as Multilink ..........................2–7
2–4. DCP Configured as a DTE ...................................2–10
2–5. Cluster Controller Configured as a DTE ..........................2–14
2–6. PLS Interface Configured as a DTE ............................2–17
2–7. U Series (DNS) Configured as a DTE ...........................2–19
2–8. U Series or IS-PC Configured as a DTE ..........................2–21
2–9. SNA Protocol Configured as a DTE .............................2–23
2–10. DTEs Configured with Permanent Virtual Circuits ...................2–25
2–11. X.29 PAD Configured to a DCP ...............................2–27
2–12. X.28/PAD Configured to X.29 Host ............................2–29
2–13. Configuring Partial DTE Addresses for Outgoing and Incoming Calls ......2–39
3–1. DCE Network Map .........................................3–4
3–2. Example of a DTE Address ...................................3–6
3–3. DCE Network Address Relationships .............................3–7
3–4. One-Node DCE Network ....................................3–10
3–5. Two-Node DCE Network ....................................3–13
3–6. DCE Network Configured with an Internal DTE .....................3–16
3–7. DCE Network Configured with Internal DTE for U Series or IS-PC DTEs
(with TS/TN Protocol) ......................................3–20
3–8. DCE Network Configured with an X.75 Interface ....................3–24
3–9. Configuring DTE Hunt Groups ................................3–34
3–10. Configuring DTE Subaddresses ...............................3–36
3–11. Configuring a Multilink Connection .............................3–39
4–1. DCP-to-DCP Trunk Configuration ...............................4–3
4–2. PDN Trunk (Statements) .....................................4–7
4–3. DCP-to-DCP Multilink Trunk Configuration ..........................4–8
4–4. Multilink Trunk (Statements) .................................4–13
4–5. DCP-to-DCP Mixed Trunk Configuration ..........................4–14
4–6. DCP-to-DCP Mixed Trunk (Statements) ..........................4–18
4–7. DCP-to-UTS 4000 Cluster Controller Configuration ..................4–19
4–8. DCP-to-UTS Cluster Controller (Statements) .......................4–23
4–9. DCP-to-U Series or IS-PC (TS/TN) Configuration ....................4–24
4–10. DCP-to-U Series or IS-PC (Statements) ..........................4–28
4–11. X.28/PAD Connection to X.29 Host ............................4–29
4–12. X.28/PAD Statements (DNS) .................................4–32
4–13. X.29 PAD Connection to OS 2200 Host (Nonconfigured DTEs) ..........4–33
4–14. X.29 PAD with Nonconfigured DTEs (Statements) ...................4–37
4–15. X.29 PAD Connection to OS 2200 Host (Configured DTEs) .............4–38
7831 5470–200 xi

Figures
xii
4–16. X.29 PAD with Configured DTEs (Statements) ......................4–42
4–17. DCP-to-Host Configuration Using PLS ...........................4–43
4–18. DCP-to-Host Using PLS (Statements) ...........................4–47
4–19. DCE Network Configuration with an X.75 Interface (DNS) ..............4–48
4–20. DCE Network (Statements) ..................................4–53
5–1. LIST LINE Command Output ..................................5–7
5–2. STAT LINE Display ........................................5–13
5–3. STAT PDTE Display .......................................5–15
5–4. STAT PTRK Display .......................................5–17
B–1. Outgoing Call Routing .......................................B–4
7831 5470–200

Tables
6–1. Throughput Class Assignment Facility Codes ......................6–20
6–2. Network Names and Mnemonics ..............................6–27
6–3. Network Names and Mnemonics for the X25DEF Statement ............6–63
6–4. NETID Values ...........................................6–64
7831 5470–200 xiii

About This Guide
Purpose
Scope
The Distributed Communications Processor (DCP) Series X.25 Packet Switched
Communications Software (PSCS) enables communications between DCPs and other
devices attached to supported packet-switched public data networks (PDNs), the
Defense Data Network (DDN), and private packet networks. It also enables point-topoint
connections between DCPs and other devices using the X.25 protocol defined by
the International Telecommunications Union/Telecommunications Standardization
Sector (ITU/TSS), formerly the Consultative Committee on International Telephone
and Telegraph (CCITT).
———————————————————————————————————————
The DCP Series X.25 Packet Switched Communications Software (PSCS)
Configuration and Operations Guide provides the information necessary to configure
X.25 PSCS on a DCP. It also offers X.25 related information on Network Management
System (NMS) commands.
———————————————————————————————————————
This guide provides the following information:
• A description of X.25 PSCS capabilities
• Task-oriented information on how to configure standard X.25 PSCS capabilities
• Task-oriented information on how to configure the DCE Network feature
• X.25 PSCS configuration examples
• Descriptions of NMS commands
• A description of X.25 PSCS configuration statements
7831 5470–200 xv

About This Guide
Audience
• Troubleshooting X.25 PSCS
• A list of X.25 PSCS reserved words
• Information on how X.25 PSCS routes outgoing calls
• NMS TRAC command file formats
———————————————————————————————————————
This guide is designed specifically for system and network administrators who
configure X.25 PSCS software, as well as for operators who issue NMS commands.
———————————————————————————————————————
Prerequisites
To use this guide to configure X.25 PSCS software, you should have Telcon and
program product configuration experience or have attended Unisys classes on these
subjects. You should also be familiar with the ITU/TSS X.25 Recommendation. To
issue NMS commands, you should be an experienced DCP operator.
———————————————————————————————————————
Organization
xvi
This guide is organized as follows:
Section 1
Introduction
Section Description
Section 2
Configuring Standard
X.25 PSCS Capabilities
Section 3
Configuring a DCE
Network
Describes X.25 PSCS capabilities, migration issues, and product
limitations and restrictions.
Provides procedural information on configuring X.25 PSCS to
provide access to a PDN, the DDN, or a private packet network.
Describes how to plan a DCE network, and configure various DCE
networks.
continued
7831 5470–200

Section Description
Section 4
Configuration Examples
Section 5
Using Network
Management Services
(NMS)
Section 6
Using X.25 PSCS
Configuration
Statements
Section 7
X.25 PSCS
Troubleshooting
Appendix A
X.25 PSCS Reserved
Words
Appendix B
X.25 PSCS Outgoing
Call Routing Concepts
Appendix C
NMS TRAC Command
Trace File Formats
Provides examples of X.25 PSCS configurations.
Explains how to use X.25 PSCS-related NMS commands.
About This Guide
Describes X.25 PSCS-related configuration statements and their
parameters and explains how to use them to configure X.25 PSCS.
Details troubleshooting methods for X.25 PSCS.
Lists X.25 PSCS reserved words.
Discusses X.25 PSCS routing concepts.
Provides examples of NMS TRAC command trace file formats.
———————————————————————————————————————
7831 5470–200 xvii

About This Guide
Notation Conventions
xviii
The following notation conventions are used in this guide:
Notation Convention Example
Commands ITALIC CAPS RECORD command
Optional information [ ] [DCP=name/netadd]
Options ITALIC CAPS R option
Parameters, parameter values ITALIC CAPS OPTIONS=RPOA parameter
Screen display monofont X.25 Reset by DCP
Single selection from group { } TYPE={H | M | L}
Statements ITALIC CAPS DTETYPE statement
Variables italic filename
Note: Uppercase letters identify information you must spell exactly as it appears.
Commands (RECORD and SWITCH) and parameters (DCP, LINE, TERM,
and so on) are examples. You can abbreviate all commands and parameters,
except for the RECORD and SWITCH commands, and their parameters.
———————————————————————————————————————
7831 5470–200

Related Product Information
About This Guide
In addition to this guide, the following Unisys documents contain helpful product
information:
Document Name/Number Description
Buyer's Guide to DCP
Communication Products
(7436 9828)
DCP Series LAN Platform
Configuration and Operations
Guide
(7831 5512)
DCP Series Open Systems
Interactive Transport
Services (OSITS)
Configuration and Operations
Guide
(7831 5587)
DCP Series SNA/net
Configuration Guide
(7831 5629)
This guide provides marketing personnel and clients with detailed
information about DCP hardware, software, network connectivity,
and product migration. It fills the gap between marketing
brochures and technical manuals.
This guide provides the following:
• Detailed information on configuring and operating the LAN
Platform, the Telcon program product that enables Telcon to
communicate over 802.3, FDDI, and Token Ring LANs
• Alphabetically arranged configuration and operation reference
information for each Telcon configuration statement and NMS
command the LAN Platform uses
• Information on the tasks associated with configuring the LAN
Platform
Use this guide with the base Telcon product operations library
and configuration library.
This guide describes how to configure OSITS on a DCP. This
guide includes the following:
• An overview of the product
• Descriptions of the required configuration statements
• Examples of typical configurations
• Operations procedures unique to OSITS
This guide describes how to configure the SNA/net program
product. This guide includes descriptions of the following:
• SNA/net features
• SNA/net software
• Telcon configuration statements
• Sample network configurations
continued
7831 5470–200 xix

About This Guide
xx
Document Name/Number Description
DCP Series TCP–IP Stack
Configuration and Operations
Guide
(7831 5546)
DCP Series Telcon
Configuration Guide
(7831 5678)
DCP Series Telcon
Configuration Reference
Manual
(7831 5686)
This guide describes how to configure TCP–IP Stack software on
a DCP. This guide includes the following:
• An overview of the product
• Descriptions of the required configuration statements
• Examples of typical configurations
• Operations procedures unique to TCP–IP Stack
This guide tells the user how to configure Telcon to enable
communication in a DCP communication network. This guide tells
the user how to configure:
• Network protocols
• Terminals
• Applications
• DSF
This guide also provides an overview of Telcon and the software
components Telcon works with, including the following:
• DCP/OS
• NMS
• Telcon program products
Use this guide with the DCP Series Telcon Configuration
Reference Manual (7831 5686).
This manual provides:
• Detailed, alphabetically arranged reference information for
each Telcon configuration statement used to configure the
base Telcon communication product, which includes TCP/IP
and OSI communication capabilities.
• An extensive set of Telcon source configuration files, which
cover the major areas of Telcon configuration.
Use this manual with the DCP Series Telcon Configuration Guide
(7831 5678).
continued
7831 5470–200

Document Name/Number Description
DCP Series Telcon
Installation Guide
(7831 5645)
DCP Series Telcon Message
Manual
(7436 0728)
DCP Series Telcon Network
Load Utility (NLU) Installation
Guide
(7436 1601)
DCP Series Telcon
Operations Guide
(7831 5785)
This guide provides information on how to
About This Guide
• Install and generate Communications Delivery software and
related program products on an OS 2200 host
• Load the generated software to Distributed Communications
Processors (DCPs)
• Verify the loaded software
This manual contains information on the following:
• Status messages, error conditions, and corrective actions for
NMS and CENLOG messages
• Directory Service Agent (DSA) messages
• Remote Files Services (RFS) messages
• Instrumentation messages
This guide describes how to install, configure, and operate the
NLU product. NLU loads a DCP with Telcon when a bootloader is
not available. NLU:
• Supports a wide set of networks
• Provides the means to use various transport protocols
between DCPs or between a DCP and an OS 2200 host.
This guide explains how to:
• Organize DCP networks using NMS consoles and commands
• Transfer files in a DCP environment
• Interpret messages
• Enable instrumentation
• Control console and logged messages
continued
7831 5470–200 xxi

About This Guide
xxii
Document Name/Number Description
DCP Series Telcon
Operations Reference
Manual
(7831 5728)
DCP Series X.25 Packet
Switched Communications
Software (PSCS)
Programming Reference
Manual
(7831 5496)
DCP Series X.25
Packet Switched
Communications Software
(PSCS)/X.28 Packet
Assembler/Disassembler
(PAD) End Use Guide
(7831 5488)
This manual contains information on the following Network
Management Services (NMS) commands and parameters:
• Telcon
• ILM NMS
• 802.3 LAN Platform NMS
• OSITS NMS
• TCP–IP Stack NMS
• Remote File System (RFS)
This manual also contains information about the following:
• Instrumentation commands and messages
• Software support procedures
This manual provides the information needed to use the DCP X.25
PSCS layer 3/4 platform interface and packet layer services (PLS)
interface to write programs that use PSCS services.
The X.28/PAD software implements recommendations that
describe how asynchronous terminals access packet-switched
public data networks. In addition to providing asynchronous
terminals with PDN access, the X.28/PAD offers synchronous
terminals this service. This guide describes how to use the
X.28/PAD from synchronous and asynchronous terminals.
———————————————————————————————————————
7831 5470–200

Section 1
Introduction
Section 1 provides an introduction to X.25 packet switched communications software
(PSCS), which includes the following:
• X.25 PSCS product overview
• X.25 PSCS limitations
• X.25 PSCS restrictions
• DCE Network limitations
• Migration issues
Section Topic
1.1
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.1.6
1.1.7
1.1.8
1.1.9
1.1.10
1.1.11
1.1.12
1.1.13
1.1.14
1.1.15
X.25 PSCS Product Overview
DCE Network Feature
ILM-20 Support
Idle Trunk Circuit Handling
CNMS Interface
Packet Network Access
Support for Standard and Proprietary Protocols
TCP/IP
OSI
SNA
DCA
Public Data Networks Supported
Special Network Certification
Special Capabilities
DTE Routing and Routing Precedence
Minimizing Packet Layer Services (PLS) DTEs
Message Tracing
1988 ITU/TSS (CCITT) Compliance
Coded Character Sets
Dynamic Line Switching
1.2 X.25 PSCS Limitations
continued
7831 5470–200 1–1

Introduction
1–2
Section Topic
1.3 X.25 PSCS Restrictions
1.4 DCE Network Limitations
1.5 DCP Loading Over X.25 Networks
1.6
1.6.1
1.6.2
Migration Issues
X25ROUTE Statement
X.29 PAD/Videotex line indicator option
Default Level 4 program option for incoming call routing
Using DTE statements as filters for incoming calls
Level 4 Program Definition for SNA/net
———————————————————————————————————————
7831 5470–200

1.1. X.25 PSCS Product Overview
Introduction
X.35 PSCS continues to support capabilities introduced in previous releases. These are
described in this section.
———————————————————————————————————————
1.1.1. DCE Network Feature
The DCE Network feature enables a DCP to function as data circuit-terminating
equipment (DCE), allowing directly attached DTEs (DADs) using the X.25 protocol to
use a Telcon network as a private X.25 packet network. In addition to network access,
a DCE network provides the following capabilities:
• Priority virtual circuits, which ensure that traffic on a low priority circuit does not
delay traffic on a higher priority circuit.
• One-way logical channels, which enable you to reserve certain logical channels for
incoming calls and others for outgoing calls.
• D-bit and M-bit implementations, which enable you to specify whether the network
or the receiving DTE provides acknowledgments. The M-bit implementation
enables communicating DTEs to maintain data integrity when the network divides
data blocks into smaller packets.
• Nonstandard default packet and window sizes, enabling a DTE to select a default
packet size other than 128 octets and a default window size other than 2.
• Flow control parameter negotiation, enabling a DTE to request specific packet and
window sizes on a per call basis during call establishment.
• Closed user groups (CUGs), providing a method of restricting access to groups of
DTEs.
• Reverse charging, which enables sending DTEs to transfer charges for a call to a
receiving DTE.
• Multilink procedure, allowing individual links to be grouped and treated as a single
link, which improves performance because the bandwidth of the group is larger
than any single link. It also improves reliability because if one link fails, others
may still be available.
• Accounting and charging information capability, enabling you to collect and log
DTE usage information on a virtual circuit basis.
7831 5470–200 1–3

Introduction
• Call switching, allowing a network operator to reroute a DTE call to another DTE.
• Hunt groups, which provide a method of configuring a single address for a group
of DTEs, enabling calls to be sent to the least active DTE.
• X.75 interface to private networks, which enables internetworking with private
networks.
———————————————————————————————————————
1.1.2. ILM-20 Support
1–4
This feature enables the X.25 PSCS packet layer to interface with a link access
procedure (LAPB) implementation executing in an ILM-20, offering the following
benefits:
• A greater number of connections. The 4 x 1 ILM-20 replaces single connection line
modules.
• Lower cost per connection.
• Increased line speeds. The ILM-20 supports an aggregate speed of up to 2 million
bits-per-second (mbps). Top speeds on other line modules cannot exceed 64,000
bps.
• Enhanced DCP performance. Achieved because the LAPB code is executing in the
line module, not the DCP I/O processor.
• Implementation of Modulo 128. Enables frame sequence numbering between 0 and
127.
This feature has been certified by European NET2 standards, and can be used on any
network that recognizes the European NET2 certification standard.
———————————————————————————————————————
7831 5470–200

1.1.3. Idle Trunk Circuit Handling
Introduction
The idle trunk circuit handling feature lowers PDN charges by implementing the
following:
• A timer that defines how long X.25 PSCS maintains an inactive switched virtual
circuit (SVC) trunk before it is cleared. Previous releases of X.25 PSCS attempted
to maintain the trunk when there was no traffic.
• A counter that defines how many attempts X.25 PSCS makes to establish an SVC
trunk before declaring a remote DCP out of service.
• A timer that defines the amount of time between attempts to reestablish an SVC
that has been cleared. Previous releases repeatedly attempted to establish an SVC.
———————————————————————————————————————
1.1.4. CNMS Interface
X.25 PSCS provides an interface to CNMS. Support for this feature enables you to
collect information by X.25 link, PDNGRP, DTE, X.29 PAD, and X.29 terminal.
———————————————————————————————————————
1.1.5. Packet Network Access
X.25 PSCS enables DCPs to access PDNs, the DDN, and private packet networks. It
offers the following features:
• Implements ITU/TSS Recommendation X.25, providing DCPs with access to packet
networks.
• Implements ITU/TSS Recommendation X.29, enabling asynchronous terminals
using a network X.3 packet assembler/disassembler (PAD) to access DCPs and OS
2200 hosts over PDNs and private packet networks.
• Implements ITU/TSS Recommendations X.3 and X.28, enabling asynchronous
terminals to communicate with foreign hosts over PDNs running applications
complying with ITU/TSS Recommendation X.29. Unisys X.28/PAD software also
provides these services for synchronous terminals. The X.28/PAD feature supports
up to 820 active terminals.
7831 5470–200 1–5

Introduction
• Provides a layer 3/4 platform interface, enabling DCP programmers to write
applications that use the X.25 services of X.25 PSCS.
• Provides a layer 4 that enables OS 2200 applications to access the X.25 services
that X.25 PSCS offers.
• Provides a feature that enables Telcon applications to use X.25 services to
communicate with U Series systems (running IS-5000 or IS-6000), Unisys personal
workstations (running IS-PC or IS-CS), UTS 4000 Cluster Controllers (running UTS
X.25 PSCS), and other DCPs.
———————————————————————————————————————
1.1.6. Support for Standard and Proprietary Protocols
TCP/IP
OSI
1–6
X.25 PSCS supports industry standard as well as proprietary protocols.
———————————————————————————————————————
X.25 PSCS supports the TCP-IP Stack, a program product that implements TCP/IP
protocols. This support enables DCPs to communicate with the following:
• TCP/IP-compliant applications across the DDN and PDNs.
• OS 2200 hosts and U Series systems (running IS-5000 or IS-6000) across the DDN.
This capability provides an interface between the TCP-IP Stack applications and
DCA applications, enabling DCPs to communicate as though they were using
Telcon connections. Full Telcon functionality is maintained.
———————————————————————————————————————
X.25 PSCS provides an interface to the OSI Transport Services (OSITS) program
product, enabling DCPs to communicate over PDNs with Open Systems
Interconnection-compliant applications.
———————————————————————————————————————
7831 5470–200

SNA
DCA
Introduction
X.25 PSCS provides an interface to the SNA/net program product, enabling DCPs to
communicate over PDNs with IBM 37xx communications controllers and PU T2.0
Cluster Controllers using the SNA protocols.
———————————————————————————————————————
X.25 PSCS provides an interface to Unisys DCA software, enabling DCPs to
communicate over PDNs with other Unisys devices.
———————————————————————————————————————
1.1.7. Public Data Networks Supported
The following lists the public data networks on which X.25 PSCS is certified to run:
Accunet (USA)
Arpac (Argentina)
Austpac (Australia)
BX.25 (USA, private operator)
Datapac (Canada)
Datex (Sweden)
Datex-P 1980 (Austria and Germany)
DCS (Belgium)
DDX (NTT Japan)
Defense Data Network (USA)
DN1 (Netherlands)
Iberpac (Spain)
Itapac (Italy)
Mexpac (Mexico)
NOPN (Norway)
NPDN (Finland)
PSS (United Kingdom)
Renpac (Brazil)
SITA (France)
Telenet ® (USA)
Telepac (Switzerland)
Telepacp (Portugal)
Transpac (France)
———————————————————————————————————————
1.1.8. Special Network Certification
X.25 PSCS earned the following special network certifications:
• Defense Data Network
• European CTS/WAN
• European NET2
• Federal Information Processing Standards (FIPS) Conformance Tests
• U.S. GOSIP
———————————————————————————————————————
7831 5470–200 1–7

Introduction
1.1.9. Special Capabilities
1–8
In addition to the basic network access capability X.25 PSCS offers, it also supports
some optional capabilities. You can use these capabilities, however, only if the
network to which your DCP is connected offers them. These capabilities are listed
below:
• Maximum packet sizes of 16, 32, 64, 128, 256, 512, 1024, 2048, and 4096 octets. You
can configure different sizes for input and output packets.
• Maximum frame sizes of 16, 32, 64, 128, 256, 512, 1024, 2048, and 4096 octets.
• Packet window sizes between 1 and 7, enabling up to 7 outstanding
unacknowledged packets.
• Frame window sizes between 1 and 7 for standard communications lines and 1
and 127 for ILM-20 lines.
• Permanent virtual circuits (PVCs), which assure that a transmitting DTE connects
to a receiving DTE. PVCs do not require call setup or clearing procedures.
• Priority virtual circuits, which ensure that traffic on a low priority circuit does not
delay traffic on a higher priority circuit.
• Closed user groups (CUGs), which restrict access to certain DTEs.
• Fast select, which enables a DTE to send a call request packet that contains up to
128 octets of data. The receiving DTE can respond with a call accepted or clear
indication packet that contains 128 octets of data as well.
• Flow control parameter negotiation, which enables a DTE to negotiate a packet
level window size on a per call basis.
• Multilink procedure, which groups links into a single entity. The multilink
procedure improves performance because the bandwidth of the group is larger
than any single link. It also improves reliability because if one link in the group
fails, others may still be available.
• One-way logical channels, which reserve certain channels for incoming traffic and
other channels for outgoing traffic.
• Recognized private operating agencies (RPOAs), which designate the intermediate
carrier (network) through which a virtual circuit connection passes to reach its
destination.
7831 5470–200

• Reverse charging, which enables the following:
– Charging outgoing calls to a receiving DTE
– Refusing incoming calls that specify reverse charging
Introduction
• Throughput class negotiation, which enables negotiated throughput rates with the
network on a per call basis.
• Transit delay, which specifies the maximum amount of time a packet has to reach
its destination.
• D-bit and M-bit implementations, which enable you to specify whether the network
or the receiving DTE provides acknowledgments. The M-bit implementation
enables communicating DTEs to maintain data integrity when the network divides
data blocks into smaller packets.
———————————————————————————————————————
1.1.10. DTE Routing and Routing Precedence
X.25 PSCS previously used three routing methods for incoming call packets: a calling
DTE address match, a protocol identifier match, and the configured default Level 4.
Previous routing precedence could not be altered by the user. The DTE Routing and
Routing Precedence feature provides a method for selecting a Level 4 based on
subaddress. It also allows you to configure the order in which the methods are
applied. The X25ROUTE statement specifies the precedence and routing used by a
given line or network.
———————————————————————————————————————
1.1.11. Minimizing Packet Layer Services (PLS) DTEs
Packet layer services (PLS) is a software feature included in X.25 PSCS that, in
combination with a host PLS driver, allows data communications between dissimilar
host systems. In earlier releases of X.25 PSCS, PLS required an EU card specifying a
DTE configuration card for every DTE that PLS connected, and one EU/DTE pair for
every line used to connect with PLS. With the release of X.25 PSCS 5R2, you can
eliminate duplicate EU/DTE pairs, increasing the speed of the connection process and
reducing initialization overhead.
———————————————————————————————————————
7831 5470–200 1–9

Introduction
1.1.12. Message Tracing
This feature provides message tracing capabilities in X.25 PSCS using the Network
Management Service (NMS) TRAC command. Trace commands are entered at the NMS
interface console to activate and control X.25 PSCS packet level 2/3 and 3/4 interface
data tracing. Trace information is then logged to the hard disk on the DCP for later
retrieval. This information is used for network debugging and software maintenance.
———————————————————————————————————————
1.1.13. 1988 ITU/TSS (CCITT) Compliance
X.25 PSCS is fully compliant with required ITU/TSS (CCITT) 1988 X.25
recommendations.
———————————————————————————————————————
1.1.14. Coded Character Sets
Internationalization allows terminals to be configured with a coded character set
(CCS). For X.25 PSCS, this includes asynchronous terminals using an X.3 PAD to
connect to the X.29 PAD interface feature, and UNISCOPE ® workstation terminals
connected to a UTS Cluster Controller running UTS X.25 PSCS software. The CCS
value may be configured using the CCS parameter on the PRCSR or TERM
configuration statements. When these terminals open DCA sessions to a host
application ($$OPEN command), the CCS value is encoded into the display zone
parameter field of the INT-1 protocol's READP response HIC string. For more
information, see Section 6.9 of this guide, “TERM — Defining a Terminal.”
———————————————————————————————————————
1.1.15. Dynamic Line Switching
1–10
Using the NMS SWT=ACTN=get/set LINE=line command for dynamic line switching
moves any resilient configured X.25 trunk to the other Telcon. If the X.25 trunk is
configured on multiple X.25 lines (that is, more than one DTE statement is used to
reference different PDNGRP statements), and only one line is switched to the other
Telcon, the entire X.25 trunk will be moved without regard to the status of the other
X.25 lines.
———————————————————————————————————————
7831 5470–200

1.2. X.25 PSCS Limitations
X.25 PSCS level 5R2 has the following capacity limitations:
• 300 lines (See Note 1)
• 135 RTC trunks
• 135 DNS trunks
• 570,000 configured virtual circuits
• 5,000 configured DTEs
• 9,890 active virtual circuits
• 820 active X.28/PAD terminals
• 300 PDNGRPs
• 1,900 logical channels for each PDNGRP
• 48 lines for each multilink group
• 8 PDNGRPs specified for multilink
• 16,000 octets of message data in combined (M-bit) packets
• 128 network types (See Note 2)
Introduction
Note: 1. X.25 PSCS supports up to 300 lines. However, X.25 PSCS allows you to
configure up to eight multilink groups. Since each multilink group can
contain up to 48 lines, in a multilink group configuration the limit is
350 lines.
2. A network type is defined by a combination of the NETID specified on a
NETWORK parameter and the global network identifier value specified
on the IDENT parameter of the X25DEF statement.
———————————————————————————————————————
7831 5470–200 1–11

Introduction
1.3. X.25 PSCS Restrictions
1–12
The following are X.25 PSCS restrictions:
• You cannot define the PDN part of a trunk by using both switched virtual circuits
(SVCs) and permanent virtual circuits (PVCs). Each trunk must be defined with
the same kind of virtual circuit.
• X.25 PSCS will not initiate a virtual circuit connection to a UTS 4000 terminal
operating under UTS X.25.
• A session to the X.28/PAD may not be established from any UTS 4000 terminal
operating under UTS X.25 PSCS.
• If you define UTS 4000 terminal clusters on a DTE statement, the PDNGRP parent
must be one of the first 16 PDNGRP statements listed in the configuration.
• X.25 PSCS does not support the data assurance feature for a TTY terminal
operating under the X.29 PAD feature or for UTS 4000 terminals operating under
UTS X.25.
• X.25 PSCS does not support the OS 2200 control statement for TTY terminals
(@@TTY). This applies only to terminals operating under the X.29 PAD feature.
• You cannot use the BREAK key on SVT-1210 terminals to emulate the
message-wait function offered by UTS. This applies only to terminals operating
under the X.29 PAD feature.
• No terminal using the X.25 protocol can specify ALOC=YES on the TERM
statement.
• X.25 PSCS does not support the 4 x 1 loadable line module.
———————————————————————————————————————
7831 5470–200

1.4. DCE Network Limitations
The DCE Network feature has the following capacity limits:
• 300 lines for each Telcon
• 1,900 logical channels for each DTE
• 255 closed user groups for each network
• Membership in six closed user groups for each DTE
Introduction
• Nine DTEs for each hunt group (all members of a hunt group must be attached to
the same Telcon)
• 16,000 octets of message data in combined (M-bit) packets from DTEs
• Only one DTE statement can be configured per Level 4 program as an internal
DTE
———————————————————————————————————————
7831 5470–200 1–13

Introduction
1.5. DCP Loading Over X.25 Networks
1–14
Downline loads and upline dumps are now supported across an X.25 network, using
the Network Load Utility. See the DCP Series Telcon Network Load Utility
Installation Guide (7436 1601) for further information regarding this product.
———————————————————————————————————————
7831 5470–200

1.6. Migration Issues
Introduction
The following sections provide information for migration between previous releases of
X.25 PSCS and X.25 release level 5R2x.
———————————————————————————————————————
1.6.1. X25ROUTE Statement
The following sections detail migration issues impacted by the X25ROUTE statement.
———————————————————————————————————————
X.29 PAD/Videotex line indicator option
X.25 PSCS release 5R1 uses a parameter option, OPTIONS=PADVTX, on the PDNGRP
statement to specify whether non-configured incoming calls with the X.29 protocol ID
in the call user data should be routed to the X.29 PAD handler or the Videotex
program product. If you do not use the X25ROUTE statement in your configuration,
you can still use this parameter option as a routing indicator. If you do use the
X25ROUTE statement, this parameter option is disabled; the routing options specified
on the X25ROUTE statement override this parameter option.
———————————————————————————————————————
Default Level 4 program option for incoming call routing
Previous releases of X.25 PSCS support specifying a default Level 4 program to which
incoming calls are routed when the other incoming call criteria have failed. The
LEVEL4 parameter on the DTETYPE statement, when referenced from either a
PDNGRP or X25DEF statement, can be used for specifying the default Level 4
program. If you do not also reference an X25ROUTE statement from either the
PDNGRP or X25DEF statements, you can still use this parameter for specifying a
default Level 4 program. If you do use the X25ROUTE statement, this parameter is
disabled; the routing options on the X5ROUTE statement override this parameter.
———————————————————————————————————————
7831 5470–200 1–15

Introduction
Using DTE statements as filters for incoming calls
1–16
Previous releases of X.25 PSCS allow you to define DTE statements for certain Level 4
programs so that only call packets from those DTEs would be accepted. The Level 4
programs are the X.29 network PAD, or one of the user-written Level 4 programs
implementing the national, international, or user-defined protocols. All four of the
Level 4 program types can be routed based on the protocol ID information contained
in the call user data field of the incoming call packet. However, if at least one DTE
statement is configured for the Level 4 program, then routing based on the protocol ID
becomes disabled and the call is accepted only if its DTE address matches the
configured address. X.25 PSCS automatically rejects incoming calls for the Level 4
program that is not configured.
In X.25 PSCS 5R2, this is no longer automatically available. This capability must be
configured using the X25ROUTE statement. To configure DTE statements for the X.29
network PAD and have all other incoming calls for the X.29 network PAD
automatically rejected, do the following:
• Use DTE statements to define the list of acceptable X.29 network PAD DTEs.
• Define the following X25ROUTE statement:
XRTEPAD X25ROUTE SEARCH=ADDRESS
Reference the statement name from the PDNGRP or X25DEF statement.
Only incoming call packets that are configured with the DTE statements will be
accepted. X.25 PSCS will automatically reject all others.
To accept incoming calls for other Level 4 types in addition to the X.29 network PAD
Level 4, routing is based on protocol ID information. For example, if other Level 4
types are OSITS and TCP-IP Stack program products, define the following X25ROUTE
statement:
XRTEPAD X25ROUTE SEARCH=(ADDRESS,PROTOCOL),;
PROTOCOL=(IPOSI,TPOSI,TPCCITT,IPTCP)
Note that the X.29 network PAD Level 4 type (X29PAD) is not included as one of the
PROTOCOL parameter's values.
———————————————————————————————————————
7831 5470–200

1.6.2. Level 4 Program Definition for SNA/net
Introduction
Previous releases of X.25 PSCS use the parameter option, LEVEL4=PDNQLLC, on the
DTETYPE statement to specify a DTE running the SNA/net Network Packet-Switching
Interface (NPSI) interface. This parameter option is no longer used; an incoming call
packet configured for and routed to the LEVEL4 definition is refused by the SNA/net
program product. Instead, use either the TGNPSI or BFNPSI parameter options for
DTEs using the SNA/net NPSI interface. These options specify the transmission group
and boundary function interfaces, respectively. Refer to the DCP Series SNA/net
Configuration Guide (7831 5629) to determine which interface to use.
———————————————————————————————————————
7831 5470–200 1–17

Section 2
Configuring Standard X.25 PSCS
Capabilities
Section 2 describes how to configure standard X.25 PSCS capabilities, that is,
capabilities associated with communication over a public data network (PDN), the
Defense Data Network (DDN), or a private packet network. See Section 3 for
procedures for configuring the DCE Network feature.
Section Topic
2.1
2.1.1
2.1.2
2.1.3
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
Configuring Basic Connections to Networks
Configuring a Connection to a PDN
Procedure
Example
Configuring a Connection to the DDN
Procedure
Example
Configuring a Multilink Connection
Procedure
Example
Defining DTEs
Configuring a DCP as a DTE
Procedure
Example
Configuring a UTS 4000 Cluster Controller as a DTE
Procedure
Example
Configuring the Packet Layer Services (PLS) Interface as a DTE
Procedure
Example
Configuring a U Series Running DNS as a DTE
Procedure
Example
Configuring a U Series or IS-PC (Running TS/TN) as a DTE
Procedure
Example
Configuring a DTE Running SNA Protocols
Procedure
Example
Configuring DTEs Using Permanent Virtual Circuits
Procedure
Example
continued
7831 5470–200 2–1

Configuring Standard X.25 PSCS Capabilities
2–2
Section Topic
2.3 Configuring an X.29 PAD
Procedure
Example
2.4 Configuring an X.28/PAD
Procedure
Example
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
2.5.7
2.5.8
Configuring Special X.25 PSCS Capabilities
Configuring Packet Size
Procedure
Example
Configuring Packet Level Window Size
Procedure
Example
Configuring Frame Size
Procedure
Example
Configuring a Frame Level Window
Procedure
Example
Configuring Permanent Virtual Circuits
Procedure
Example
Configuring the CALLED and CALLING Options
Procedure
Example
Configuring Partial DTE Addresses
Procedure 1: Configuring Partial DTE Addresses for Outgoing Calls
Procedure 2: Configuring Partial DTE Addresses for Incoming Calls
Procedure 3: Configuring Partial DTE Addresses for Outgoing and
Incoming Calls
Configuring Incoming Call Routing Precedence
Procedure
Examples
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.1 Configuring Basic Connections to Networks
This section consists of three modules that describe how to configure basic
connections to networks. It discusses the following subjects:
• Configuring a connection to a PDN
• Configuring a connection to the DDN
• Configuring a multilink connection
In some instances, these basic connections provide all the configuration information
X.25 PSCS requires. For example, when the DCP is connected to a single network and
will communicate with OSI and TCP/IP devices, these simple configurations may be
sufficient. In other instances, however, they simply serve as core configurations upon
which the other configurations described in this section are built.
———————————————————————————————————————
2.1.1 Configuring a Connection to a PDN
This section explains how to define a basic X.25 PSCS configuration (a single DCP
connection [line] to a single PDN). Figure 2–1 illustrates this configuration.
Figure 2–1. DCP Connection Configured to a PDN
———————————————————————————————————————
7831 5470–200 2–3

Configuring Standard X.25 PSCS Capabilities
Procedure
2–4
Provide the following configuration statements:
• A PRCSR statement to define the DCP.
• An X25DEF statement.
– Specify the NETWORK parameter or ensure that the N1, N2, T1, T2, T3,
L2OPT, and L3OPT parameter values are appropriate for the network to
which the DCP is connected.
• A PDNGRP statement to define the DCP connection to the network. Specify the
following:
– A reference to a PRCSR statement
– A reference to an X25DEF statement
– A logical channel range and type
• An LCLASS statement that specifies the following:
–
defines a standard X.25 line module
– A line speed
–
Defines a direct, synchronous, full-duplex line, which the X.25 protocol
requires.
• A LINE statement that defines the line to the PDN. Specify the following:
– A reference to a PDNGRP statement
– A reference to an LCLASS statement
– A physical address
———————————————————————————————————————
7831 5470–200

Example
Configuring Standard X.25 PSCS Capabilities
The following is an example of a single connection to the Telenet network.
———————————————————————————————————————
2.1.2 Configuring a Connection to the DDN
This section explains how to configure a single DCP connection to the DDN. Figure
2–2 illustrates this configuration. It differs from the configuration in Section 2.1.1 in
that the X25DEF statement specifies and the PDNGRP statement
specifies a DTE address for the DCP, which the DDN requires.
Figure 2–2. DCP Connection Configured to the DDN
———————————————————————————————————————
7831 5470–200 2–5

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–6
Provide the following configuration statements:
• A PRCSR statement to define the DCP.
• An X25DEF statement that specifies
• A PDNGRP statement to define the DCP connection to the network. Specify the
following:
– A reference to a PRCSR statement
– A reference to an X25DEF statement
– A logical channel range and type
– A DTE address for the DCP
• An LCLASS statement that specifies the following:
–
defines a standard X.25 line module
– A line speed
–
Defines a direct, synchronous, full-duplex line, which the X.25 protocol
requires.
• A LINE statement that defines the line to the DDN. Specify the following:
– A reference to a PDNGRP statement
– A reference to an LCLASS statement
– A physical address
———————————————————————————————————————
The following is an example of a single connection to the DDN.
———————————————————————————————————————
7831 5470–200

2.1.3 Configuring a Multilink Connection
Procedure
Configuring Standard X.25 PSCS Capabilities
This section explains how to configure a multilink connection. The previous
configurations show the usual one-to-one relationship between LINE and PDNGRP
statements. With a multilink configuration, however, up to 48 LINE statements can be
associated with a single PDNGRP statement. In fact, all the lines in the multilink must
reference a single PDNGRP statement. Figure 2–3 illustrates a multilink connection.
Note: Before configuring a multilink connection, make sure that your network
supports it.
Figure 2–3. DCP Connection Configured as Multilink
———————————————————————————————————————
Provide the following configuration statements:
• A PRCSR statement to define the DCP.
• An X25DEF statement.
– Specify the NETWORK parameter or ensure that the N1, N2, T1, T2, T3,
L2OPT, and L3OPT values are appropriate for the network.
7831 5470–200 2–7

Configuring Standard X.25 PSCS Capabilities
Example
2–8
• A PDNGRP statement that specifies the following:
– A reference to a PRCSR statement
– A reference to an X25DEF statement
– A logical channel range and type
– A multilink window size ()
– , which specifies the multilink option for this PDNGRP
• An LCLASS statement that specifies the following:
– which defines a standard X.25 line module
– A line speed
–
Defines a direct, synchronous, full-duplex line, which the X.25 protocol
requires.
• A LINE statement for each line associated with this multilink connection. Each
LINE statement must specify the following:
– A reference to the same PDNGRP statement
– A reference to an LCLASS statement
– A physical address
———————————————————————————————————————
The following example defines a multilink connection to a private network. Since the
NETWORK parameter on the X25DEF statement cannot define connections to a
private network, the L2OPT parameter specifies appropriate values for this network.
———————————————————————————————————————
7831 5470–200

2.2 Defining DTEs
Configuring Standard X.25 PSCS Capabilities
This section describes how to define configured DTEs. It builds on the basic network
connections described earlier and does not repeat the steps required to configure a
network connection.
This section describes how to define the following systems as configured DTEs:
• Another DCP
• A UTS 4000 Cluster Controller
• PLS
• U Series system running the DNS protocol
• U Series or IS-PC system running the TS/TN protocol
• Systems running the SNA protocols
• PVCs
The following systems can be defined as configured DTEs, but are not required to be
defined as such:
• TCP/IP
• OSI
• X.29 PAD
• Videotex
———————————————————————————————————————
7831 5470–200 2–9

Configuring Standard X.25 PSCS Capabilities
2.2.1 Configuring a DCP as a DTE
2–10
This section describes how to define a remote DCP as a DTE. It builds on the basic
network connections described in Section 2.1.1, “Configuring a Connection to a PDN”
and Section 2.1.3, “Configuring a Multilink Connection.” Since the DDN requires the
TCP/IP protocols, do not use the procedures described in Section 2.1.2, “Configuring a
Connection to the DDN,” with this procedure.
Figure 2–4 illustrates this configuration. Instructions for configuring the idle trunk
capability are provided as well.
Note: DCPs must be defined as configured DTEs.
Figure 2–4. DCP Configured as a DTE
———————————————————————————————————————
7831 5470–200

Procedure
Provide the following additional configuration statements:
• A PRCSR statement to define the other DCP.
• A TRUNK statement.
Configuring Standard X.25 PSCS Capabilities
Although neither the PRCSR nor the TRUNK statements have X.25 PSCS specific
parameters, they are included here for clarity.
• A DTETYPE statement that specifies the following on the LEVEL4 parameter:
–
Specifies PDNTRUNK as the Level 4 program to which X.25 PSCS should
route data received from the DTE that is defined later in this procedure.
– The maximum number of switched virtual circuits this trunk may use. The
default is 1.
– The number of attempts to initially establish, or to reestablish, a virtual circuit
connection that has been cleared because of inactivity. Specify between 0 and
255 attempts. If you do not specify a value or if you specify 0, X.25 PSCS
continues to attempt to initially establish or reestablish a circuit until it is
successful.
– The amount of time between attempts to initially establish or reestablish a
virtual circuit connection that has been cleared because of inactivity. Specify
between 0 and 65,535 seconds. If you do not specify a value or if you specify
0, an attempt is made every 60 seconds.
– The amount of time between transmission of network data units (NDUs),
before a circuit is cleared. Specify between 0 and 65,535 seconds. If you do
not specify a value or you specify 0, X.25 PSCS does not automatically clear
the circuit.
– The diagnostic code that X.25 PSCS encodes in clear packets when a trunk
goes into an idle condition. Specify a value between 1 and 255. The default is
168.
Note: You must specify these values in the order listed. See the example
following this procedure for more information.
7831 5470–200 2–11

Configuring Standard X.25 PSCS Capabilities
2–12
• A basic connection for the remote DCP. See Section 2.1, “Configuring Basic
Connections to Networks,” for information on configuring basic connections to
networks.
• Two DTE statements to define the DCPs as DTEs. Specify the following:
– A reference to a PDNGRP statement.
– A reference to a DTETYPE statement.
– A reference to a TRUNK statement. Specify PDN on this parameter as well,
indicating that this is a PDN only trunk.
– A DTE address.
———————————————————————————————————————
7831 5470–200

Example
Configuring Standard X.25 PSCS Capabilities
The following example shows a DCP-to-DCP trunk configuration. The LEVEL4
parameter on the DTETYPE statement specifies PDNTRUNK. The DTETYPE also
defines a maximum of ten switched virtual circuits for this trunk and the following
values for idle trunk handling:
• 10 attempts to reestablish a virtual circuit that has been cleared
• 90 seconds between attempts to reestablish a virtual circuit that has been cleared
• 90 seconds between transmission of NDUs before a circuit is cleared
• A diagnostic code of 150 to indicate that a trunk is in an idle state
———————————————————————————————————————
7831 5470–200 2–13

Configuring Standard X.25 PSCS Capabilities
2.2.2 Configuring a UTS 4000 Cluster Controller as a DTE
2–14
This section describes how to define a UTS 4000 Cluster Controller running UTS X.25
PSCS software as a DTE. It builds on the basic network connections described in
Section 2.1.1, “Configuring a Connection to a PDN” and Section 2.1.3, “Configuring a
Multilink Connection.” Since the DDN requires the TCP/IP protocols, do not use the
procedures described in Section 2.1.2, “Configuring a Connection to the DDN,” with
this procedure.
Figure 2–5 illustrates this configuration.
Note: UTS 4000 Cluster Controllers must be defined as DTEs.
Figure 2–5. Cluster Controller Configured as a DTE
———————————————————————————————————————
7831 5470–200

Procedure
Provide the following additional configuration statements:
• A DTETYPE statement that specifies .
Configuring Standard X.25 PSCS Capabilities
• A DTE statement to define the UTS 4000 Cluster Controller as a DTE. Specify the
following:
– A reference to a PDNGRP statement
– A reference to the DTETYPE statement just defined
– A DTE address
• A GROUP statement to function as the CLSTR statement's parent.
• A CLSTR statement. Specify the following:
– A reference to a GROUP statement
– A reference to the DTE statement just defined
• A TERM statement for each workstation screen supported on the UTS 4000
Cluster Controller. Specify the following:
– A reference to the CLSTR statement just defined
– A terminal type, either UTS20W or UTS40W
– A terminal address
———————————————————————————————————————
7831 5470–200 2–15

Configuring Standard X.25 PSCS Capabilities
Example
2–16
The following example shows a UTS 4000 Cluster Controller configured as a DTE.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.2.3 Configuring the Packet Layer Services (PLS) Interface as a
DTE
This section describes how to define foreign hosts using the Packet Layer Services
(PLS) host interface as a DTE. It builds on the basic network connections described in
Section 2.1.1, “Configuring a Connection to a PDN” and Section 2.1.3, “Configuring a
Multilink Connection.” Since the DDN requires the TCP/IP protocols, do not use the
procedures described in Section 2.1.2, “Configuring a Connection to the DDN,” with
this procedure.
Figure 2–6 illustrates this configuration.
Note: Foreign hosts that use the PLS interface must be defined as DTEs.
Figure 2–6. PLS Interface Configured as a DTE
———————————————————————————————————————
7831 5470–200 2–17

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–18
Provide the following additional configuration statements:
• An XEU statement that references a NETADR statement which defines an
OS 2200 host network address.
• A DTETYPE statement that specifies the PLS host interface as a layer 4 program
with the LEVEL4=PLS parameter option.
• A DTE statement to define the foreign host as DTE. Specify the following:
– A reference to the PDNGRP statement
– A reference to the DTETYPE statement just defined
– The DTE address of the foreign host
• An EU statement that references a PRCSR statement and specifies the following:
– The PLS host interface as a transport service user
– The DTE statement just defined
– The XEU statement just defined
———————————————————————————————————————
The following example shows a PDN connection to a foreign host using the PLS host
interface.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.2.4 Configuring a U Series Running DNS as a DTE
This section describes how to define a remote U Series system running the DNS
protocol as a DTE. It builds on the basic network connections described in Section
2.1.1, “Configuring a Connection to a PDN” and Section 2.1.3, “Configuring a Multilink
Connection.” Since the DDN requires the TCP/IP protocols, do not use the procedures
described in Section 2.1.2, “Configuring a Connection to the DDN,” with this
procedure.
Figure 2–7 illustrates this configuration. Instructions for configuring the new idle trunk
capability are provided as well.
Note: U Series systems running DNS must be defined as configured DTEs.
Figure 2–7. U Series (DNS) Configured as a DTE
———————————————————————————————————————
7831 5470–200 2–19

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–20
Provide the following additional configuration statements:
• A TRUNK statement.
Although this statement does not have X.25 PSCS specific parameters, it is included
here for clarity.
• A DTETYPE statement that specifies the following on the LEVEL4 parameter:
– PDNTRUNK
– The maximum number of switched virtual circuits for this trunk. The default is
one.
• A DTE statement to define the remote U Series as a DTE. Specify the following:
– A reference to a PDNGRP statement.
– A reference to a DTETYPE statement.
– A reference to a TRUNK statement. Specify PDN on this parameter as well,
indicating that this is a PDN only trunk.
– A DTE address.
———————————————————————————————————————
The following example shows a U Series running DNS as a DTE. The LEVEL4
parameter on the DTETYPE statement specifies PDNTRUNK. The DTETYPE also
defines a maximum of ten switched virtual circuits for this trunk.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.2.5 Configuring a U Series or IS-PC (Running TS/TN) as a DTE
This section describes how to define a remote U Series system running the TS/TN
protocol as a DTE, or a PC running IS-PC with the TS/TN protocol. It builds on the
basic network connections described in Section 2.1.1, “Configuring a Connection to a
PDN” and Section 2.1.3, “Configuring a Multilink Connection.” Since the DDN requires
the TCP/IP protocols, do not use the procedures described in Section 2.1.2,
“Configuring a Connection to the DDN,” with this procedure.
Figure 2–8 illustrates this configuration.
Note: U Series systems and IS-PC systems running TS/TN must be defined as
configured DTEs.
Figure 2–8. U Series or IS-PC Configured as a DTE
———————————————————————————————————————
7831 5470–200 2–21

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–22
Provide the following additional configuration statements:
• A DCATS statement that references a PRCSR statement.
DCATS statements do not include X.25 PSCS specific parameters. This statement
is provided for clarity.
• A DTETYPE statement that specifies
• A DTE statement to define the U Series or IS-PC as a DTE. Specify the following:
– A reference to a PDNGRP statement
– A reference to the DTETYPE statement just defined
– A DTE address
– A reference to the DCATS statement just defined
———————————————————————————————————————
The following example shows a PDN connection to a U Series or IS-PC system.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.2.6 Configuring a DTE Running SNA Protocols
This section describes how to define a system running SNA protocols as a DTE. It
builds on the basic network connections described in Section 2.1.1, “Configuring a
Connection to a PDN” and Section 2.1.3, “Configuring a Multilink Connection.” Since
the DDN requires the TCP/IP protocols, do not use the procedures described in
Section 2.1.2, “Configuring a Connection to the DDN,” with this procedure.
Figure 2–9 illustrates this configuration.
Note: 1. Systems running the SNA protocols must be defined as configured DTEs.
2. The SNA/net program product must be installed for this configuration.
Figure 2–9. SNA Protocol Configured as a DTE
———————————————————————————————————————
7831 5470–200 2–23

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–24
Provide the following additional configuration statements:
• A DTETYPE statement that specifies .
• A DTE statement to define the remote system as a DTE. Specify the following:
– A reference to a PDNGRP statement
– A reference to the DTETYPE statement just defined
– A DTE address
Note: Refer to the DCP Series SNA/net Configuration Guide (7831 5629) for
additional configuration statements required by SNA/net.
———————————————————————————————————————
The following example configures a PU T2.0 device running the SNA protocols as a
DTE.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.2.7 Configuring DTEs Using Permanent Virtual Circuits
This section describes how to configure DTEs that use permanent virtual circuits
(PVCs). DTEs that use PVCs are supported by X.25 PSCS for the following layer 4
programs: another DCP, systems running the Packet Layer Services host interface, and
systems running the SNA/net protocols.
It builds on the basic network connections described in Section 2.1.1, “Configuring a
Connection to a PDN” and Section 2.1.3, “Configuring a Multilink Connection.” Since
the DDN requires the TCP/IP protocols, do not use the procedures described in
Section 2.1.2, “Configuring a Connection to the DDN,” with this procedure.
Figure 2–10 illustrates this configuration.
Figure 2–10. DTEs Configured with Permanent Virtual Circuits
———————————————————————————————————————
7831 5470–200 2–25

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–26
Provide the following additional configuration statements:
• A DTETYPE statement that specifies the layer 4 program being used by the DTE
with the LEVEL4 parameter.
• A DTE statement to define the DTE using PVCs. Specify the following:
– A reference to a PDNGRP statement
– A reference to the DTETYPE statement just defined
– The range of logical channel numbers associated with the DTE using PVCs
———————————————————————————————————————
The following example shows a PDN connection to a DTE using PVCs.
———————————————————————————————————————
7831 5470–200

2.3 Configuring an X.29 PAD
Configuring Standard X.25 PSCS Capabilities
This section describes how to configure the X.29 PAD feature, which enables terminals
attached to a foreign or network packet assembler/disassembler (PAD) to access the
DCP and communicate with an OS 2200 host. It builds on the basic network
connections described in Section 2.1.1, “Configuring a Connection to a PDN” and
Section 2.1.3, “Configuring a Multilink Connection.” Since the DDN requires the TCP/IP
TELNET protocol for terminal access, do not use the procedures described in Section
2.1.2, “Configuring a Connection to the DDN,” with this procedure.
Figure 2–11 illustrates this configuration.
Figure 2–11. X.29 PAD Configured to a DCP
———————————————————————————————————————
7831 5470–200 2–27

Configuring Standard X.25 PSCS Capabilities
Procedure
Example
2–28
Provide the following configuration statements:
• A PDNPAD statement to define the X.3 operating characteristics.
See the discussion on the PDNPAD statement in Section 6, “X.25 PSCS
Configuration Statements,” for information on X.3 operating parameters.
• TERM statements to define the terminals that will access the X.29 PAD. Specify
the following:
– A reference to the PDNPAD statement just defined.
– A terminal type on the TYPE parameter. Specify TTY, UTS10B, UTS10C, or
DCT500.
Note: You can define the terminals attached to the foreign or network PAD as
configured DTEs. However, this limits X.29 PAD access to configured DTEs
only. Calls from other DTEs are cleared. To configure DTEs, provide a DTE
statement that references PDNGRP and DTETYPE statements and specifies
the DTE address of the calling PAD.
The X25ROUTE statement can also be used to define subaddresses so that
incoming calls from an X.29 PAD can be routed to either the X.29 PAD
handler or Videotex product handler.
———————————————————————————————————————
The following example shows an X.29 PAD configuration that does not define DTEs.
———————————————————————————————————————
7831 5470–200

2.4 Configuring an X.28/PAD
Configuring Standard X.25 PSCS Capabilities
This section describes how to configure the X.28/PAD, which provides access from
asynchronous and synchronous terminals attached to the DCP to foreign hosts across
packet networks. It builds on the basic network connections described in Section
2.1.1, “Configuring a Connection to a PDN” and Section 2.1.3, “Configuring a Multilink
Connection.” Since the DDN requires the TCP/IP TELNET protocol for terminal access,
do not use the procedures described in Section 2.1.2, “Configuring a Connection to the
DDN,” with this procedure.
Figure 2–12 illustrates this configuration.
Figure 2–12. X.28/PAD Configured to X.29 Host
———————————————————————————————————————
7831 5470–200 2–29

Configuring Standard X.25 PSCS Capabilities
Procedure
2–30
Provide the following additional statements:
• For asynchronous terminals (only), specify at least two EU statements, one for the
terminal type and the other for the data protocol. For the terminal type statement,
specify the following on the EU statement:
– A reference to a PRCSR statement
– One of the following terminal types on the TYPE parameter:
for VT terminals (VT, SVT)
for TTY terminals (TTY, DCT500, UTS10C)
For the data protocol, specify the following on the second EU statement:
– A reference to a PRCSR statement
– One of the following data presentation protocols on the TYPE parameter:
for the INT-1 protocol
for a character-mode protocol
When configuring for all types of asynchronous terminals, you may have to specify
all four types of EU statements.
• An EU statement to define the DCP as a PAD for asynchronous terminals and an
EU statement for synchronous terminals. Specify the following:
– A reference to a PRCSR statement.
– .
– Either a network mnemonic or a reference to an X25DEF statement on the
NETWORK parameter. You can find the correct mnemonic in the discussion
on the EU statement in Section 6, “X.25 PSCS Configuration Statements.”
– For asynchronous terminals, specify the EUPRCSR parameter to reference a
PRCSR statement and specify .
7831 5470–200

Example
Configuring Standard X.25 PSCS Capabilities
• An XEU for the asynchronous terminals and an XEU for the synchronous
terminals that will use the X.28/PAD. Specify the following:
– For asynchronous terminals:
A reference on the DESTSSU parameter to the EU statement that defines the
asynchronous X.28 PAD interface.
– For synchronous terminals, specify a reference on the DESTSSU parameter to
the EU statement that defines the synchronous X.28/PAD interface.
• Standard LCLASS, LINE, and TERM statements for definition of terminals and the
lines that connect them to the DCP.
• Optionally, to enable X.28/PAD users to make calls by specifying a DTE statement
name rather than a DTE address, define X.29 hosts as configured DTEs. To do
this, provide standard DTE statements and a DTETYPE statement that specifies
.
———————————————————————————————————————
The following example shows an X.28/PAD configured for asynchronous and
synchronous terminal use.
7831 5470–200 2–31

Configuring Standard X.25 PSCS Capabilities
2–32
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.5 Configuring Special X.25 PSCS Capabilities
This section describes how to configure optional features. Optional features are built
on the configurations described in Section 2.1, “Configuring Basic Connections to
Networks,” any of which can form the basic network connection.
———————————————————————————————————————
2.5.1 Configuring Packet Size
Procedure
Example
This section describes how to configure the maximum size input and output packets
for a DTE. X.25 PSCS supports the following sizes: 16, 32, 64, 128, 256, 512, 1024, 2048,
and 4096 octets.
———————————————————————————————————————
On the DTETYPE statement, specify the size of input packets and the size of output
packets:
———————————————————————————————————————
The following example shows a DTE configured for input packets of 128 octets and
output packets of 256 octets.
———————————————————————————————————————
2.5.2 Configuring Packet Level Window Size
Procedure
This section describes how to configure a DTE packet level window size, which is the
number of packets that can be transmitted without acknowledgment. X.25 PSCS
supports packet level windows between 1 and 7 unacknowledged packets.
———————————————————————————————————————
On the DTETYPE statement, specify the size of the input and output windows:
———————————————————————————————————————
7831 5470–200 2–33

Configuring Standard X.25 PSCS Capabilities
Example
The following example shows a DTE configured for an input window of two
outstanding packets and an output window of five outstanding packets.
———————————————————————————————————————
2.5.3 Configuring Frame Size
Procedure
Example
2–34
This section describes how to configure the maximum size of a frame's information
field. X.25 PSCS supports the following frame sizes: 16, 32, 64, 128, 256, 512, 1024,
2048, and 4096 octets.
———————————————————————————————————————
On the X25DEF statement, specify .
———————————————————————————————————————
The following example shows a configuration specifying a frame size of 256 octets.
———————————————————————————————————————
7831 5470–200

2.5.4 Configuring a Frame Level Window
Procedure
Example
Configuring Standard X.25 PSCS Capabilities
This section describes how to configure the frame level window, which defines the
maximum number of frames that can be sent or received without acknowledgment.
X.25 PSCS supports a frame level window between 1 and 7 unacknowledged frames
on standard line modules and, optionally, between 1 and 127 unacknowledged frames
on ILM-20 lines.
———————————————————————————————————————
On the X25DEF statement, specify the following:
• The number of outstanding frames to allow on the L2WINDOW parameter
• if the configuration is for an ILM-20 line and you want the extended
window size
———————————————————————————————————————
The following example shows a configuration specifying a frame level window of five
octets.
———————————————————————————————————————
7831 5470–200 2–35

Configuring Standard X.25 PSCS Capabilities
2.5.5 Configuring Permanent Virtual Circuits
Procedure
Example
2–36
This section shows you how to configure permanent virtual circuits.
———————————————————————————————————————
• On the PDNGRP statement, specify the following:
– The first logical channel
– The last logical channel
–
This specifies that these logical channels form permanent virtual circuits.
• On the DTE statement, specify the following:
– The first logical channel. This must fall within the range of logical channels
specified on the PDNGRP statement.
– The last logical channel. This must fall within the range of logical channels
specified on the PDNGRP statement.
———————————————————————————————————————
The following example shows DTEs configured for permanent virtual circuits.
Note: Ensure that the ranges defined on the parameter do not overlap other
DTE definitions.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.5.6 Configuring the CALLED and CALLING Options
Procedure
Example
This section explains how to configure the and options, which enable
you to instruct X.25 PSCS to process a DTE statement only on incoming calls ()
or on outgoing calls ().
———————————————————————————————————————
On the DTE statement, specify one of the following:
•
This specifies that X.25 PSCS processes the DTE statement on outgoing calls only.
•
This specifies that X.25 PSCS processes the DTE statement on incoming calls only.
———————————————————————————————————————
The following example specifies a DTE statement processed on incoming calls only.
Since the PDNTRUNK LEVEL4 specified on the associated DTETYPE statement must
function as a configured DTE, and X.25 PSCS will not process this DTE statement on
outgoing calls, PDNTRUNK cannot initiate calls. It can, however, receive calls, since
the DTE statement will be processed on incoming calls.
———————————————————————————————————————
7831 5470–200 2–37

Configuring Standard X.25 PSCS Capabilities
2.5.7 Configuring Partial DTE Addresses
This section explains how to configure partial DTE addresses, which means X.25 PSCS
uses only the partial address to make routing decisions, enabling you to define many
DTEs with the same DTE statement.
This section provides three procedures:
• Configuring DTE partial addresses for routing outgoing calls
• Configuring DTE partial addresses for incoming calls
• Configuring DTE partial addresses for incoming and outgoing calls
———————————————————————————————————————
Procedure 1: Configuring partial DTE addresses for outgoing calls
On the DTE statement, specify the following:
•
Specifies that the DTE address defined on this statement is a partial address.
• A partial DTE address
Enclose this address in single quotation marks. If you are routing based on
network type, for example, this address would consist of only the data network
identifier code (DNIC) portion.
———————————————————————————————————————
Procedure 2: Configuring partial DTE addresses for incoming calls
2–38
On the DTE statement, specify the following:
•
Specifies that the DTE address defined on this statement is a partial address and
that X.25 PSCS processes this DTE statement only on incoming calls.
• A partial DTE address
Enclose this address in single quotation marks.
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
Procedure 3: Configuring partial DTE addresses for outgoing and incoming
calls
On the DTE statement, specify the following:
•
Specifies that the DTE address defined on this statement is a partial address and
that X.25 PSCS processes this DTE statement on both incoming and outgoing calls.
• A partial DTE address
Enclose this address in single quotation marks.
Example 1
Example 1 specifies the abbreviated address option for outgoing calls. The partial DTE
address is a DNIC, which enables the DTE statement to define every DTE on the
network.
Example 2
Example 2 specifies the abbreviated address option for incoming calls. The partial
DTE address is a DNIC, which enables the DTE statement to define every DTE on the
network. The option means that X.25 PSCS processes this DTE statement only
on incoming calls.
Example 3
Example 3 specifies the abbreviated address option for incoming and outgoing calls.
The partial DTE address is a DNIC, which enables the DTE statement to define every
DTE on the network. The and options together means that X.25 PSCS
processes this DTE statement on both incoming and outgoing calls.
———————————————————————————————————————
7831 5470–200 2–39

Configuring Standard X.25 PSCS Capabilities
2–40
Figure 2–13 illustrates this configuration.
Figure 2–13. Configuring Partial DTE Addresses for Outgoing and Incoming Calls
———————————————————————————————————————
7831 5470–200

Configuring Standard X.25 PSCS Capabilities
2.5.8 Configuring Incoming Call Routing Precedence
Procedure
This section explains how to configure incoming call packet routing precedence with
the X25ROUTE statement. When an incoming call is received from a network, X.25
PSCS allows you to select which incoming call packet fields to use for routing
purposes. You can also specify the selection order. The available incoming call packet
fields include:
• Calling DTE address
• Protocol ID information in the call user data field
• Address digits appended to the called DTE address (subaddress digits)
You can also route all incoming call packets to a single layer 4 program regardless of
the incoming call packet contents.
If none of the routing methods selected directs the call to a layer 4 program, then X.25
PSCS directs the call back to the network.
———————————————————————————————————————
Add an X25ROUTE statement to specify the order that incoming call packet contents
are examined by X.25 PSCS. On the SEARCH parameter, specify one or more of the
following parameters in any order:
• Specify the ADDRESS option if you want to route the call based on matching the
incoming call packet's calling DTE address with an address configured on a DTE
statement. If an address match occurs, the call is routed to the layer 4 program
identified on the LEVEL4 parameter of the DTETYPE statement referenced by the
DTE statement.
• Specify the PROTOCOL option if you want to route the call based on protocol ID
information in the incoming call packet's call user data field. Not all layer 4
programs available to X.25 PSCS are routed by this method; only a select list are
supported (see Note 1). You must specify the layer 4 programs on the X25ROUTE
PROTOCOL parameter.
• Specify the SUBADR option of you want to route the call based on the subaddress
digits in the called DTE address field. You must use the X25ROUTE SUBADR
parameter to define subaddress digits for a layer 4 program. Only a select list of
layer 4 programs are supported.
7831 5470–200 2–41

Configuring Standard X.25 PSCS Capabilities
Examples
2–42
• Specify the LEVEL4 option if you want all incoming call packets to be routed to a
single layer 4 program. Not all layer 4 programs available to X.25 PSCS are
supported.
Note: 1. Only a select list of layer 4 programs are used for the PROTOCOL,
SUBADR, and LEVEL4 parameter options. They include: IPOSI, TPOSI,
TPCCITT, IPTCP, X29PAD, PDNPID, PDNIPID, PDNUPID, and
VIDEOTEX. These are the names defined for the DTETYPE statement's
LEVEL4 parameter. Other layer 4 programs must be configured and
routed using DTE statements, making them unavailable for these routing
options.
2. Because the LEVEL4 parameter option instructs a call to be routed to a
specific layer 4 program regardless of the incoming call packet contents,
once you specify the LEVEL4 option on a SEARCH parameter, any
subsequently specified parameter options are unusable. Therefore, when
specifying the LEVEL4 option, ensure that it is the last option selected.
Reference the X25ROUTE statement from either a PDNGRP or X25DEF statement. If
you want to define the routing method for only a specific network connection (line),
specify the X25ROUTE on the PDNGRP; if you want to use the routing method for all
network connections, specify it on the X25DEF statement.
———————————————————————————————————————
Example 1
Example 1 shows an OSITS product interface implementation requiring limited access,
allowing only a predefined list of DTE addresses to use the interface. Any incoming
call received from a DTE that is not listed requires special handling by another layer 4
interface.
• Provide an X25ROUTE statement that first routes incoming call packets based on
their calling DTE addresses. If no match occurs, the call is routed to a user-written
layer 4 interface for handling the unwarranted call packet.
• Provide a DTETYPE statement with a LEVEL4=TPOSI parameter option for the
OSITS transport protocol.
• Provide a DTE statement for all DTEs that are authorized to use the OSITS
transport protocol interface.
Note: This routing configuration disables the more commonly used protocol ID
method for routing to the OSITS product.
7831 5470–200

Example 2
Configuring Standard X.25 PSCS Capabilities
Example 2 shows incoming call routing for DTEs switching layer 4 programs (or
protocols) on a per call basis between OSITS and a user-written layer 4 program.
Because configured DTE addresses can only be associated with a single layer 4
program, the address-only routing method will not work. This example shows how
both the X.29/PAD interface and the Videotex program product can be supported on a
single X.25 line.
• Provide an X25ROUTE statement that routes calls to Videotex or a user-written
layer 4 program based on subaddress digits in the called DTE address. If no
subaddress digit match occurs, however, use the call packet's protocol ID
information for routing.
This example assumes the packet network supports subaddressing and that the DTEs
attached to the network are capable of appending subaddress digits on a per call
basis. If no match occurs based on the subaddress digits, the protocol ID is used for
routing.
Note: Do not specify subaddress digits that match the last digits of the local or
called DTE addresses attached to X.25 PSCS.
———————————————————————————————————————
7831 5470–200 2–43

Section 3
Configuring a DCE Network
This section explains how to plan and configure the DCE Network feature. The tasks
you perform to configure a DCE network require a reorientation for users that
configure PSCS to access packet networks. Previously, you configured DCPs to
function as DTEs, requesting and using network services. With DCE Network, you
configure DCPs to become the packet network, providing network access and services
for other systems functioning as DTEs.
Although DCE Network uses a Telcon network for routing between DCEs, it does not
require special Telcon configuration. Telcon considerations, therefore, are not covered
in this section. See the DCP Series Telcon Configuration Guide (7831 5678) for
information on configuring the Telcon network.
Section Topic
3.1
3.1.1
3.1.2
3.1.3
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
Planning the Network
Drawing the Network Map
Rules for Creating Network Addresses
Selecting Statements
Configuring the DCE Network
Configuring a One-Node DCE Network
Procedure
Example
Adding a Node and DTEs to a DCE Network
Procedure
Example
Configuring an Internal DTE
Procedure
Example
Configuring an Internal DTE for U Series or IS-PC DTEs Running with the
TS/TN Protocol
Procedure
Example
Configuring an X.75 Interface to Another Network
Procedure
Example
continued
7831 5470–200 3–1

Configuring a DCE Network
3–2
Section Topic
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
3.3.7
3.3.8
Configuring Special DCE Network Capabilities
Configuring a Closed User Group
Procedure
Example
Configuring Priority Virtual Circuits
Procedure
Example
Configuring Reverse Charging
Procedure
Example
Configuring Flow Control Negotiation
Procedure
Example
Configuring DTE Hunt Groups
Procedure
Example
Configuring DTE Subaddresses
Procedure
Example
Configuring an ILM-20 Connection to a DTE
Procedure
Example
Configuring a Multilink Protocol Connection
Procedure
Example
———————————————————————————————————————
7831 5470–200

3.1 Planning the Network
Configuring a DCE Network
This section explains how to plan a DCE network, which requires you to perform the
following tasks:
• Draw a network map
• Determine DTE addresses
• Select the statements you need to configure the network
———————————————————————————————————————
3.1.1 Drawing a Network Map
This section explains how to create a map, or picture, of the network, which should
include the following:
• DCPs functioning as routing nodes. Although neither X.25 PSCS nor DCE Network
software will be installed on these DCPs, you may find it helpful to include them
in your map.
• DCPs functioning as DCEs.
• DCPs serving as DCEs and gateways to other packet networks.
• DTEs, both internal and external.
– An internal DTE is a Level 4 program that routes data to an attached
OS 2200 system. Not all LEVEL4 interfaces are supported. For example, the
program may be the OSITS program product for routing data to an attached
OS 2200 system.
– An external DTE is directly attached (DAD) to the DCP without an intervening
packet network (see Section 3.3.6).
Note: The DCE Network feature does not support connections between two internal
DTEs. Only external/external and external/internal connections are
supported.
———————————————————————————————————————
7831 5470–200 3–3

Configuring a DCE Network
3–4
Figure 3–1 provides an example of a simple network map.
Figure 3–1. DCE Network Map
———————————————————————————————————————
7831 5470–200

3.1.2 Rules for Creating Network Addresses
Configuring a DCE Network
This section explains how to create addresses. As the system or network
administrator, you are responsible for assigning addresses to the following:
• The network itself
• Individual nodes
• Individual DTEs
Together these addresses uniquely identify the network, a specific DCE node, and a
specific DTE. This is similar to the way that an area code, prefix, and extension
identify a specific telephone. This section explains how to create addresses; see
Section 3.1.3, “Selecting Statements,” for a description of the statements used to assign
these addresses.
A complete network address can be 6 to 14 digits long and consists of the following
parts:
• A data network identifier code (DNIC), which identifies the network. The ITU/TSS
assigns DNICs to all public data networks (PDNs). You can find these assignments
in ITU/TSS Recommendation X.121. Since you are creating a DNIC for a private
network, you may choose any four-digit number. If, however, your network
provides a gateway to public data networks, do not choose a number that the
ITU/TSS has already assigned.
• A DCE node number, which consists of one to four digits. Assign these numbers
to DCE nodes only. Routing nodes do not require this number. The number of
digits used depends on the number of DCE nodes in the network. If your network
will never have more than nine nodes, a single digit scheme is sufficient. For
larger networks, two-, three-, and even four-digit numbers may be required. For
clarity, choose a consistent and meaningful numbering scheme.
• A specific DTE identifier, which consists of one to six digits.
———————————————————————————————————————
7831 5470–200 3–5

Configuring a DCE Network
3–6
Figure 3–2 describes DTE address components.
1111 0001 2100
Figure 3–2. Example of a DTE Address
Note: 1. If you configure DTE hunt groups, the last digit of the DTE identifier has
special significance. See Section 3.3.5, “Configuring DTE Hunt Groups”
discussed later in this section for more information.
2. If you plan on using subaddresses, do not use all 14 digits to specify a
standard address. See Section 3.3.6, “Configuring DTE Subaddresses”
discussed later in this section for more information.
———————————————————————————————————————
7831 5470–200

Figure 3–3 illustrates address component relationships.
Configuring a DCE Network
• The DNIC is 9999. This number, which must be exactly four digits, forms the first
part of all DTE addresses.
• DCP 1 has a DCE node number of 01. DCP 2 has no DCE node number; it does
not function as a DCE. The other DCEs in the network have two-digit DCE node
numbers. Each DTE attached to DCP 1 will have a DNIC of 9999 and a DCE node
number of 01 as the first six digits of its DTE address.
• DTE A has a DTE address of 999901001. The last three digits provide the DTE
identifier. Although DTE A and DTE C both use 001 as DTE identifiers, their DCE
node numbers are different, so messages intended for one will not be routed to
the other.
Figure 3–3. DCE Network Address Relationships
7831 5470–200 3–7

Configuring a DCE Network
3.1.3 Selecting Statements
3–8
This section describes the DCE Network configuration statement requirements,
including information on the statements that carry addressing information. The
following are the statements used to configure a DCE Network:
• EU statements. Use one for each DCP that functions as a DCE. Specify
TYPE=DCPNET and the DNIC and DCE node identifier portion of a DTE address
on this statement.
• An XEU statement for each EU statement (except in one-node DCE networks,
where XEU statements are not required).
• X25NET statements.
– Each DCE node requires an X25NET statement for every other DCE node in
the network to which it routes calls. For example, if the network has three
DCE nodes, each node requires two X25NET statements, one for each of the
other DCEs. DCE networks with only one node do not require X25NET
statements. In addition, each node requires an X25NET statement for each
X.75 gateway to a PDN.
• A PDNGRP statement for each line configured.
– Specify OPTIONS=DAD
– If you configure the multilink capability, more than one LINE statement
references a single PDNGRP statement.
• A DTE statement for each internal and directly attached DTE (DAD). This
statement's DTEADR parameter requires a complete DTE address. DTEs directly
attached to the DCE network must be configured DTEs. Nonconfigured DTEs are
not supported.
• A LINE statement for each physical line.
• At least one DTETYPE statement that specifies LEVEL4=PDNNET.
7831 5470–200

• At least one X25DEF statement that specifies:
– NETWORK=PSCSNET
– DTX=YES (optional, but recommended)
Configuring a DCE Network
The NETWORK parameter specifying PSCSNET is not required. You may select
any NETWORK parameter option that is compatible with the directly attached
DTE (DAD). See Table 6–3 for a list of available NETWORK parameter names. See
Table 6–4 for a description of how each network is defined regarding other
X25DEF statement parameters.
Note: X.25 PSCS supports a point-to-point X.25 connection between a DCP and a
DTE configuration, where the calls are routed to a DCP by the calling DTE
address, which is specified on the DTEADR parameter of the DTE statement.
By using the DAD option on the PDNGRP statement, the DCE Network
feature routes calls based on the called DTE address, which is specified on
the DTEADR parameter.
———————————————————————————————————————
7831 5470–200 3–9

Configuring a DCE Network
3.2 Configuring the DCE Network
The following procedures describe DCE network configuration. To provide focus to
the discussion, optional parameters are not used and Telcon-specific statements
(except the PRCSR statements) and parameters are not described.
———————————————————————————————————————
3.2.1 Configuring a One-Node DCE Network
3–10
This section explains how to configure a basic DCE network, consisting of a single
DCP functioning as a DCE and two attached DTEs. Figure 3–4 illustrates this
configuration.
Figure 3–4. One-Node DCE Network
———————————————————————————————————————
7831 5470–200

Procedure
Provide the following statements:
• A PRCSR statement to define the DCP.
• A DTETYPE statement that specifies LEVEL4=PDNNET.
• An X25DEF statement that specifies the following:
– NETWORK=PSCSNET
– DTX=YES
Configuring a DCE Network
The NETWORK parameter specifying PSCSNET is not required. You may select
any NETWORK parameter option that is compatible with the directly attached
DTE (DAD). See Table 6–3 for a list of available NETWORK parameter names. See
Table 6–4 for a description of how each network is defined regarding other
X25DEF statement parameters.
• An LCLASS statement that specifies the following:
– LPH=X25PKT
X25PKT defines a standard X.25 line. To use an ILM-20, see Section 3.3.7,
“Configuring an ILM-20 Connection to a DTE,” which is presented later in this
section.
– A line speed
– OPTIONS=(DIR,SYFD)
DCE software supports direct lines only, and X.25 is a synchronous, full-duplex
protocol.
• An EU statement that specifies the following:
– A reference to a PRCSR statement.
– TYPE=DCPNET
– A DCENODE number (DCENODE=`dstadd'), which consists of the DNIC and
DCE node number portions of a full DTE address. Enclose this number in
single quotation marks.
7831 5470–200 3–11

Configuring a DCE Network
Example
3–12
• A PDNGRP statement for each line. On the PDNGRP, specify the following:
– A reference to the X25DEF statement.
– A logical channel range and type. Do not specify permanent virtual circuits.
DCE Network does not support them.
– OPTIONS=DAD
• A LINE statement for each DTE.
– Each LINE statement must reference a different PDNGRP statement unless
you configure multilink.
– Each LINE statement must reference an LCLASS statement, although many
LINE statements can reference the same LCLASS statement.
• A DTE statement for each DTE you configure. Specify the following:
– A reference to a PDNGRP and a DTETYPE statement.
– A complete DTE address on the DTEADR parameter. Enclose this address in
single quotation marks.
Note: Because this network consists of a single node, X25NET and XEU statements
are not required.
———————————————————————————————————————
The following is an example of a configuration for a one-node network with two
attached DTEs.
———————————————————————————————————————
7831 5470–200

3.2.2 Adding a Node and DTEs to a DCE Network
Configuring a DCE Network
This section describes the additional statements required to add a DCP with two DTEs to
the previous configuration, using the Telcon proprietary protocol DTP. Figure 3–5
illustrates this configuration.
Figure 3–5. Two-Node DCE Network
———————————————————————————————————————
7831 5470–200 3–13

Configuring a DCE Network
Procedure
3–14
Provide the following additional statements:
• A PRCSR statement.
• An EU statement associated with the new DCP. Specify the following:
– A reference to the new PRCSR statement.
– TYPE=DCPNET
– A DCENODE number (DCENODE=`dstadd'), which consists of the DNIC and
DCE node number portions of a full DTE address. Enclose this number in single
quotation marks.
• XEU statements, paired with each EU statement. Specify the following:
– The associated PRCSR statement on the DS parameter.
– The name of the paired EU statement on the DESTTSU parameter. Enclose this
name in single quotation marks.
• Two X25NET statements.
– Associate each statement with one of the DCPs through the PRCSR parameter.
– Each statement must include a DESTID parameter that specifies the DCE node
number of the other DCP. Enclose this number in single quotation marks.
– Each statement must specify an XEU parameter that references the EU
associated with the other DCP.
• Two PDNGRP statements, one for each line connecting the new DCE to its DTEs.
Specify the following on these statements:
– A reference to the X25DEF statement.
– A logical channel range and type. Do not specify permanent virtual circuits. DCE
Network does not support them.
– OPTIONS=DAD
• Two LINE statements, one for each of the new DTEs.
– Each LINE statement must reference a different PDNGRP statement unless you
configure multilink.
– Each LINE statement must reference an LCLASS statement.
– Each LINE statement must specify a line address.
7831 5470–200

Example
Configuring a DCE Network
• Two DTE statements, one for each new DTE. Specify the following on each
statement:
– A reference to a PDNGRP and a DTETYPE statement.
– A complete DTE address on the DTEADR parameter. Enclose this address in
single quotation marks.
———————————————————————————————————————
The following is an example of a two-node network with two DTEs attached to each
node. It builds on the example of a one-node network discussed previously.
———————————————————————————————————————
7831 5470–200 3–15

Configuring a DCE Network
3.2.3 Configuring an Internal DTE
3–16
This section describes the additional statements required to configure an internal DTE
on the two-node network configured in Section 3.2.2. A configured DTE is one of the
standard Level 4 programs specified on the DTETYPE statement.
Note: Not all Level 4 programs support being configured as internal DTEs.
The following example shows the communication capability between any of the
external DADs and the internal Level 4 program, where the Level 4 program provides
an interface to an OS 2200 host. Figure 3–6 illustrates this configuration.
DTE Address = 9999002001
DTE
DTE
DTEDCE3
DCE Node
# 9999002
DCE Node
# 9999001
DTEDCE1
DTE Address = 9999001001
PRC2
OSITS
DCP
DTE Address = 9999002002
PRC2
PRC1
DTE
DTE
DTEDCE4
Internal DTE Address = 9999001003
OS 2200
DTEDCE2
DTE Address = 9999001002
Figure 3–6. DCE Network Configured with an Internal DTE
DTEDCE5
007XL200.CDR
———————————————————————————————————————
7831 5470–200

Procedure
Configuring a DCE Network
Provide the following additional statements for defining an internal DTE:
• A DTETYPE statement that identifies the Level 4 program. The following is a list
of Level 4 programs that can be configured as internal DTEs:
– IPOSI, which specifies the OSITS internet protocol component of the OSITS
program product. Use this Level 4 program for connectionless network
service.
– TPOSI, which specifies the OSITS transport service of the OSITS program
product. Use this Level 4 program for connection-oriented network service.
– TPCCITT, which specifies the ITU/TSS defined OSITS transport service
component of the OSITS program product.
– IPTCP, which specifies the TCP–IP Stack internet protocol.
– PDNX28, which specifies the X.28/PAD-to-X.29 host pairing.
– PDNDXA, which specifies an X.25 connected PC or U Series system running
DCA software. If you specify this LEVEL4, specify the DCATS parameter on
the associated DTE statements.
– PDNNPID, which specifies a local implementation of network protocol.
– PDNIPID, which specifies a local implementation of an international protocol.
– PDNUPID, which specifies a local implementation of a user-defined protocol.
– VIDEOTEX, which specifies the VIDEOTEX program product.
– TGNPSI, which specifies a transmission group connection (SNA/net).
– BFNPSI, which specifies a boundary function connection (SNA/net).
– PLS, which specifies the packet layer services host interface software.
– CORPNET, which specifies the CORP/net program product.
7831 5470–200 3–17

Configuring a DCE Network
Example
3–18
• A DTE statement that specifies the following:
– A reference to a PDNGRP statement. This PDNGRP statement must have the
parameter option OPTIONS=DAD specified.
– A reference to the DTETYPE statement just defined.
– A DTE address. This address should conform to the DCE Network
conventions. Enclose it in single quotation marks.
Note: 1. PDNTRUNK, PDNUNIS, X29PAD, and AIR/net cannot be configured as
internal DTEs.
2. PLS, and the TGNPSI and BFNPSI Level 4 programs, can only be used on
a single node. Routing to or from these internal DTEs to external DTEs
cannot be performed across more than one node.
3. Only one DTE statement can be configured per Level 4 program as an
internal DTE.
———————————————————————————————————————
The following is an example of a two-node network with two DTEs attached to each
node and an internal DTE. It builds on the example in Section 3.2.2. The internal DTE
is TPOSI, which identifies the OSITS transport service of the OSITS program product.
7831 5470–200

Configuring a DCE Network
———————————————————————————————————————
7831 5470–200 3–19

Configuring a DCE Network
3.2.4 Configuring an Internal DTE for U Series or IS-PC DTEs
Running with the TS/TN Protocol
3–20
This section describes the additional statements required to configure an internal DTE
for U Series or IS-PC DTEs running with the TS/TN protocol on the two-node network
configured in Section 3.2.2. U Series or IS-PC DTEs running with the TS/TN protocol
require DTE statements. These DTE statements must reference unique DCATS
statements.
The following example shows communication capability between any of the external
DADs and the internal Level 4 program, where the Level 4 program provides an
interface to an OS 2200 host. Figure 3–7 illustrates this configuration.
DTE A ddress = 9 999002001
DTE
DTE
D TE D C E 3
D C E N o d e
# 9 9 9 9 0 0 2
D C E N o d e
# 9 9 9 9 0 0 1
D TE D C E 1
DTE A ddress = 9 999001001
PRC2
TS / TN
DCP
DTE A ddress = 9 999002002
PR C 2
PR C 1
DTE
DTE
D TE D C E 4
Internal D TE A ddress = 9 999001003
O S 2 2 0 0
D TE D C E 2
DTE A ddress = 9 999001002
D TE D C E 5
065XL200.CDR
Figure 3–7. DCE Network Configured with Internal DTE for U Series or IS-PC DTEs
(with TS/TN Protocol)
———————————————————————————————————————
7831 5470–200

Procedure
Provide the following additional statements:
Configuring a DCE Network
• A DCATS statement for each external DTE. A DCATS statement references a
PRCSR statement. Each external DTE must reference a unique DCATS statement,
regardless of the Telcon processor. To ensure this uniqueness, duplicate each
DCATS statement definition for both Telcon processors.
• A SESSN statement for each external DTE on the Telcon processor connected to
the OS 2200 host. Each SESSN statement references the unique DCATS statement
defined for each external DTE. The SESSN statements also reference a common
DCATS statement which is defined for the OS 2200 host. The sets of logical
subchannel numbers must be coordinated with those defined on the OS 2200 host,
and on the U Series or IS-PC software.
• A DTETYPE statement for the internal DTE that specifies LEVEL4=PDNDXA.
• A DTE statement for each node for the internal DTE that specifies the following:
– A reference to a PDNGRP statement. This PDNGRP statement must have the
parameter option OPTIONS=DAD specified.
– A reference to the DTETYPE statement just defined.
– A DTE address. This address should conform to the DCE Network
conventions. Enclose it in single quotation marks.
– A reference to a unique DCATS statement just defined.
———————————————————————————————————————
7831 5470–200 3–21

Configuring a DCE Network
3–22
Example
The following is an example of a two-node network with two DTEs attached to each
node and an internal DTE. It builds on the example in Section 3.2.2. The internal DTE
is PDNDXA, which identifies the TS/TN protocol interface for U Series systems
running IS-6000 software, or Unisys personal workstations running IS-PC software.
7831 5470–200

Configuring a DCE Network
———————————————————————————————————————
7831 5470–200 3–23

Configuring a DCE Network
3.2.5 Configuring an X.75 Interface to Another Network
3–24
This section describes the additional statements and parameters required to add an
X.75 interface to the two-node network discussed in Section 3.2.2. Figure 3–8
illustrates this network. Configuring this interface enables communication with DTEs
on another network. Calls originating on the DCE network can always be connected,
but calls from DTEs on the other network can be connected only if the other network
specifies the DCE network DNIC in the called DTE address field of call request
packets. This requires the other network to recognize the DCE network as another
network, such as in an X.75 gateway interface. This capability is usually not offered by
PDNs.
Figure 3–8. DCE Network Configured with an X.75 Interface
———————————————————————————————————————
7831 5470–200

Procedure
Provide the following additional statements and parameters:
Configuring a DCE Network
• An X25DEF statement to define the DCP connection to the other network. The
example specifies the Telenet network.
• An X25NET statement that specifies the following:
– A reference to the PRCSR statement that defines the gateway DCP.
– The DNIC of the other network. Specify this DNIC on the DNICID parameter.
– The XEU of the gateway DCP.
• A PDNGRP statement that defines the connection to the other network and
specifies the following:
– A reference to a PRCSR statement that defines the gateway DCP.
– A reference to the X25DEF statement just specified.
– A logical channel range and type.
– OPTIONS=X75
This statement should not specify OPTIONS=DAD.
• A LINE statement that specifies the following:
– A reference to a PDNGRP and an LCLASS statement.
– A physical address.
• A DTE statement.
This statement provides X.25 PSCS with the routing information it requires to
determine the correct network on which to place a call. It is required because the
DCP is connected to more than one packet network. See Appendix B for more
information on routing.
Specify the following:
– A reference to the PDNGRP statement just defined.
– A DTE address. If this is a partial address, specify OPTIONS=ABBRVADR as
well.
– A reference to a DTETYPE statement that specifies LEVEL4=PDNNET.
———————————————————————————————————————
7831 5470–200 3–25

Configuring a DCE Network
Example
3–26
The following example is similar to the one presented in Section 3.2.2, “Adding a Node
and DTEs to a DCE Network,” except it adds an X.75 interface to the Telenet network.
———————————————————————————————————————
7831 5470–200

Configuring a DCE Network
3.3 Configuring Special DCE Network Capabilities
The following sections describe how to configure special DCE network capabilities.
———————————————————————————————————————
3.3.1 Configuring a Closed User Group
This section explains how to configure the network to provide support for DTEs to
join closed user groups (CUGs). A CUG is a security arrangement that enables you to
restrict access to a DTE to CUG members only. The following rules apply to CUG
configurations:
• DCE networks support up to 255 CUGs.
• An individual DTE can belong to up to six CUGs.
• Any DTE can belong to any CUG.
• CUG membership is limited to DTEs attached to the DCE network. DTEs attached
to other networks cannot be part of a DCE network CUG.
• You can configure a DTE to restrict incoming and outgoing calls to CUG members
only, or permit DTEs outside of the group to call or be called by members.
• You assign CUG membership on a DTE-by-DTE basis using the DCECUG
parameter on the DTE statement.
———————————————————————————————————————
7831 5470–200 3–27

Configuring a DCE Network
Procedure
Example
3–28
Provide a DTE statement that specifies the following:
• A reference to a PDNGRP statement.
• A reference to a DTETYPE statement.
• A DTE address. This address should conform to the DCE network conventions.
Enclose it in single quotation marks.
• The CUG options you want associated with this DTE (on the DCECUG parameter).
The following are CUG options:
– ALLOWI specifies that a DTE may accept calls originating outside its closed
user group.
– ALLOWO specifies that a DTE may make calls to devices outside its closed
user group.
– ALLOWIO specifies that a DTE may make and receive calls to and from
devices outside its closed user group.
– CLOSED specifies that a DTE may not make or receive calls to or from DTEs
outside the closed user group.
• The number of the CUG or CUGs to which this DTE is assigned.
———————————————————————————————————————
The following example uses DTE statements to assign four DTEs to membership
among two different CUGs. The first two DTEs, DTEDCE1 and DTEDCE2, each belong
to two different CUGs. The last two DTEs, DTEDCE3 and DTEDCE4, each belong to
only one CUG. Both DTEDCE1 and DTEDCE2 can make calls to DTEDCE3 and
DTEDCE4. Both DTEDCE3 and DTEDCE4 can make calls to DTEDCE1 and
DTEDCE2. Neither DTEDCE3 or DTEDCE4 can call each other. Because all CUGs are
closed, none of the DTEs can make calls outside of their CUGs.
7831 5470–200

Configuring a DCE Network
When DTEDCE1 makes a call to DTEDCE4, for example, it must encode the CUG
facility code. The facility parameter must be a 2. This is the index of the DTEDCE4
CUG number (4) configured on the DCECUG parameter. When either DTEDCE3 or
DTEDCE4 make a call, they must always encode a CUG facility parameter of 1. That is
the only valid index value. Any other index value causes the DCE Network feature to
clear the call attempt.
———————————————————————————————————————
7831 5470–200 3–29

Configuring a DCE Network
3.3.2 Configuring Priority Virtual Circuits
Procedure
Example
3–30
This section explains how to configure the network to support a DTE's request for
priority virtual circuits. Based on Annex G of the 1988 version of ITU/TSS
Recommendation X.25 (Bluebook), a DTE can request a virtual circuit priority on a
per-call basis. The ITU/TSS specified facility marker and priority are encoded in the
DTE's call request packet. If a DTE requests a priority call on a line that does not
support the feature, the call is cleared, indicating that priority circuits are not
available. The DCE network supports priorities between 0 (lowest) and 3 (highest). If
a call requests a priority higher than 3, the call is accepted and a priority of 3 is used.
———————————————————————————————————————
Provide a PDNGRP statement that specifies the following:
• A reference to PRCSR and X25DEF statements.
• A logical channel range and type. Do not specify permanent virtual circuits. DCE
Network does not support them.
• OPTIONS=(DAD,HIPRI)
– DAD specifies that the associated DTE is a directly attached DTE (DAD).
– HIPRI specifies that the DCE-to-DTE connection defined by the PDNGRP
supports priority virtual circuits.
———————————————————————————————————————
The following is an example of a DCE-to-DTE connection configured to support
priority circuits.
———————————————————————————————————————
7831 5470–200

3.3.3 Configuring Reverse Charging
Procedure
Example
Configuring a DCE Network
This section explains how to configure a DCE so that a directly attached DTE is never
charged for a call. Charges are always incurred by the other DTE, regardless of which
DTE initiated the call.
Note: If two DTEs are both configured for reverse charging, they cannot
communicate with each other.
———————————————————————————————————————
Provide a DTE statement that specifies the following:
• A reference to a PDNGRP statement.
• A reference to a DTETYPE statement.
• A DTE address. This address should conform to the DCE Network conventions.
Enclose it in single quotation marks.
• OPTIONS=NOCHG
———————————————————————————————————————
The following is an example of a DCE configured to support reverse charging. The
DTE defined by DTEDCE1 will never be charged for a call.
———————————————————————————————————————
7831 5470–200 3–31

Configuring a DCE Network
3.3.4 Configuring Flow Control Negotiation
Procedure
Example
3–32
This section explains how to configure a DCE for flow control negotiation. If this
option is configured, the DCE will encode all call packets to a directly attached DTE
(DAD) with the flow control negotiation facility. This enables the DAD to determine
packet and window size on a per call basis. If the DTETYPE statement does not define
a packet and window size, the defaults become the maximum size. The default for
packet size is 128 octets. The default window size is 2. The default output sizes are the
input sizes.
———————————————————————————————————————
Provide a DTE statement that specifies the following:
• A reference to a PDNGRP statement.
• A reference to a DTETYPE statement.
• A DTE address. This address should conform to the DCE network conventions.
Enclose it in single quotation marks.
• OPTIONS=FLOWC
———————————————————————————————————————
The following is an example of a DCE configured for flow control negotiation.
———————————————————————————————————————
7831 5470–200

3.3.5 Configuring DTE Hunt Groups
Procedure
Configuring a DCE Network
This section explains how to configure DTE hunt groups. A hunt group is a collection
of DTEs with a common DTE address. Hunt groups enable load sharing because X.25
PSCS can route calls to the least busy DTE in the group. DTEs defined as hunt group
members can still be accessed individually, however.
———————————————————————————————————————
• Define directly attached connections.
• Provide a dummy DTE statement. While this statement does not define a DTE, it
does define the hunt group address. You must specify the following:
– A reference to a PDNGRP statement, which must be the same PDNGRP
statement referenced that the first real DTE statement references.
– A reference to a DTETYPE statement.
– A DTE address on the DTEADR parameter. This address consists of the
following:
A data network identification code (DNIC)
A DCE node identifier
A DTE identifier whose last digit is zero
– OPTIONS=HGROUP
• Provide up to nine additional DTE statements, each of which must conform to the
following configuration requirements:
– Each must specify a reference to a PDNGRP and a DTETYPE statement.
– Each DTE address specified on a DTEADR parameter must be identical to the
address of the DTE that preceded it, except for the last digit, which must be
incremented by one. Consequently, the address of the first DTE that follows
the dummy must end in a one. The address of the second DTE must end in a
two, and so on.
– Each must specify OPTIONS=HGROUP.
———————————————————————————————————————
7831 5470–200 3–33

Configuring a DCE Network
Example
3–34
The following example shows you how to configure a hunt group consisting of three
DTEs. The first DTE statement is the dummy. The three that follow define real DTEs.
———————————————————————————————————————
Figure 3–9 illustrates this configuration.
Figure 3–9. Configuring DTE Hunt Groups
———————————————————————————————————————
7831 5470–200

3.3.6 Configuring DTE Subaddresses
Procedure
Example
Configuring a DCE Network
This section explains how to configure DTE subaddresses. This capability enables you
to append additional address digits to the called DTE address portion of call packets.
X.25 PSCS ignores the additional digits when routing the call to the called DTE. The
DTE's software provides interpretation.
Typically, this capability is used for routing, either when more than one physical
device is attached to a single multiplexed line or when more than one software entity
can be the destination of a single DTE's incoming packets.
To implement DTE subaddressing, assign a fourth field to a complete DTE address,
which normally consists of a DNIC, a DCE node number, and a DTE identifier. The
fourth field consists of the subaddressing digits.
———————————————————————————————————————
Provide a DTE statement that specifies the following:
• A reference to a PDNGRP statement.
• A reference to a DTETYPE statement.
• A DTE address. This address should not include the subaddressing digits. Enclose
the address in single quotation marks.
• OPTIONS=ABBRVADR
Note: Do not specify the subaddressing digits in configuration. X.25 PSCS only
needs to know that it is to ignore all digits beyond those specified on the
DTEADR parameter.
———————————————————————————————————————
The following example configures a DTE that specifies subaddressing. Since the
address contains ten digits, up to four digits are available for subaddressing.
———————————————————————————————————————
7831 5470–200 3–35

Configuring a DCE Network
3–36
Figure 3–10 illustrates this configuration.
Figure 3–10. Configuring DTE Subaddresses
———————————————————————————————————————
7831 5470–200

3.3.7 Configuring an ILM-20 Connection to a DTE
Procedure
Example
Configuring a DCE Network
This section explains how to configure an ILM-20 connection to a DTE.
———————————————————————————————————————
Provide an LCLASS statement that specifies the following:
• LPH=(ILML,`PSCSHDLC')
– ILML is required for the ILM Platform to initialize this line.
– PSCSHDLC is the name of the DCP file that holds X.25 PSCS preregistration
information. This name is required. Enclose it in single quotation marks.
• The line speed
The ILM-20 supports speeds of up to two mbps. The combined speed of all lines
connected to a single ILM-20 cannot exceed two mbps.
• OPTIONS=(DIR,SYFD)
– The ILM LAPB implementation supports direct lines only
– X.25 is a synchronous, full-duplex protocol
———————————————————————————————————————
The following is an example of an LCLASS statement used to define an ILM-20 line for
X.25 PSCS DCE Network.
———————————————————————————————————————
7831 5470–200 3–37

Configuring a DCE Network
3.3.8 Configuring a Multilink Protocol Connection
Procedure
3–38
This section explains how to configure a DCE to support a multilink protocol
connection. Because a multilink connection groups many lines under a single DTE
address, it provides greater throughput than a single line. Typically, there is a
one-to-one relationship between LINE and PDNGRP statements. With multilink, up to
48 lines (LINE statements) are associated with a single PDNGRP statement.
Configuring multilink requires that all lines in the multilink reference the same
PDNGRP statement, and the DTE be configured for multilink as well. Each DCP can
be configured for up to eight multilink PDNGRPs.
———————————————————————————————————————
Provide the following configuration statements:
• A PDNGRP statement that specifies the following:
– A multilink window size (MLPW=window)
The window size defines the maximum number of unacknowledged frames
that can be outstanding.
– OPTIONS=(DAD,MLP)
DAD is required for all DCE Network PDNGRP statements. It defines a
directly attached DTE (DAD).
MLP specifies the multilink option for this PDNGRP.
• An LCLASS statement that specifies the following:
– LPH=X25PKT for a standard X.25 line module or LPH=(ILML,`PSCSHDLC')
for an ILM-20
– A line speed
– OPTIONS=(DIR,SYFD)
• A LINE statement for each line associated with this multilink connection:
– Each LINE statement must reference a single PDNGRP statement.
– Up to 48 LINE statements can reference the same PDNGRP statement.
• A DTE statement that specifies the following:
– A reference to the PDNGRP statement previously defined.
– A reference to a DTETYPE statement.
– A reference to a DTE address.
———————————————————————————————————————
7831 5470–200

Example
Configuring a DCE Network
The following example defines a multilink connection using a standard X.25 line
module.
———————————————————————————————————————
Figure 3–11 illustrates this configuration.
Figure 3–11. Configuring a Multilink Connection
———————————————————————————————————————
7831 5470–200 3–39

Section 4
Configuration Examples
Section 4 consists of configuration examples related to X.25 PSCS. Each example
consists of the following:
• A brief introduction describing the configuration
• An overview illustration showing the hardware connected by the configuration
• Configuration listings, showing the configuration statements used in the example
configuration
• An illustration showing relationships of pertinent statements
Section Topic
4.1 DCP-to-DCP Trunk
CMS configuration example
Telcon configuration example
4.2 DCP-to-DCP Multilink Trunk
CMS configuration example
Telcon configuration example
4.3 DCP-to-DCP Mixed Trunk
CMS configuration example
Telcon configuration example
4.4 DCP-to-UTS 4000 Cluster Controller
CMS configuration example
Telcon configuration example
4.5 DCP-to-U Series or IS-PC (TS/TN)
CMS configuration example
Telcon configuration example
continued
7831 5470–200 4–1

Configuration Examples
4–2
Section Topic
4.6 X.28/PAD
Telcon configuration example
4.7 X.29 PAD with Nonconfigured DTEs
CMS configuration example
Telcon configuration example
4.8 X.29 PAD with Configured DTEs and X25ROUTE Statement
CMS configuration example
Telcon configuration example
4.9 DCP-to-Remote Host Using PLS
CMS configuration example
Telcon configuration example
4.10 Two-Node DCE Network
CMS configuration example
Telcon configuration example
———————————————————————————————————————
7831 5470–200

4.1 DCP-to-DCP Trunk
Configuration Examples
The following example configures a PDN trunk connection between two DCPs. Figure
4–1 illustrates this configuration.
Figure 4–1. DCP-to-DCP Trunk Configuration
———————————————————————————————————————
7831 5470–200 4–3

Configuration Examples
CMS configuration example
4–4
———————————————————————————————————————
7831 5470–200

Telcon configuration example
Configuration Examples
7831 5470–200 4–5

Configuration Examples
4–6
7831 5470–200

Configuration Examples
———————————————————————————————————————
Figure 4–2 shows the statement relationships for this configuration.
Figure 4–2. PDN Trunk (Statements)
———————————————————————————————————————
7831 5470–200 4–7

Configuration Examples
4.2 DCP-to-DCP Multilink Trunk
4–8
The following example configures a multilink trunk. Figure 4–3 illustrates this
configuration.
Figure 4–3. DCP-to-DCP Multilink Trunk Configuration
———————————————————————————————————————
7831 5470–200

CMS configuration example
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–9

Configuration Examples
Telcon configuration example
4–10
7831 5470–200

Configuration Examples
7831 5470–200 4–11

Configuration Examples
4–12
———————————————————————————————————————
7831 5470–200

Figure 4–4 shows statement relationships for this configuration.
Figure 4–4. Multilink Trunk (Statements)
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–13

Configuration Examples
4.3 DCP-to-DCP Mixed Trunk
4–14
The following example shows two DCPs connected by a UDLC line and a PDN trunk.
Figure 4–5 illustrates this configuration.
Figure 4–5. DCP-to-DCP Mixed Trunk Configuration
———————————————————————————————————————
7831 5470–200

CMS configuration example
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–15

Configuration Examples
Telcon configuration example
4–16
7831 5470–200

Configuration Examples
7831 5470–200 4–17

Configuration Examples
4–18
———————————————————————————————————————
Figure 4–6 shows statement relationships for this configuration.
Figure 4–6. DCP-to-DCP Mixed Trunk (Statements)
———————————————————————————————————————
7831 5470–200

4.4 DCP-to-UTS 4000 Cluster Controller
Configuration Examples
The following example configures a connection between a DCP and a UTS 4000
Cluster Controller with six workstation terminals.
Figure 4–7 illustrates this configuration.
Figure 4–7. DCP-to-UTS 4000 Cluster Controller Configuration
———————————————————————————————————————
7831 5470–200 4–19

Configuration Examples
CMS configuration example
4–20
———————————————————————————————————————
7831 5470–200

Telcon configuration example
Configuration Examples
7831 5470–200 4–21

Configuration Examples
4–22
———————————————————————————————————————
7831 5470–200

Figure 4–8 illustrates the statement relationships for this configuration.
Configuration Examples
Figure 4–8. DCP-to-UTS Cluster Controller (Statements)
———————————————————————————————————————
7831 5470–200 4–23

Configuration Examples
4.5 DCP-to-U Series or IS-PC (TS/TN)
4–24
The following example shows a DCP connected to a remote DCA termination system,
which can be either a U Series system or a personal computer running Information
Services software. Two PDN lines connect the DCP to the PDN, providing additional
throughput.
Figure 4–9 illustrates this configuration.
Figure 4–9. DCP-to-U Series or IS-PC (TS/TN) Configuration
———————————————————————————————————————
7831 5470–200

CMS configuration example
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–25

Configuration Examples
Telcon configuration example
4–26
7831 5470–200

Configuration Examples
———————————————————————————————————————
7831 5470–200 4–27

Configuration Examples
4–28
Figure 4–10 shows statement relationships for this configuration.
Figure 4–10. DCP-to-U Series or IS-PC (Statements)
———————————————————————————————————————
7831 5470–200

4.6 X.28/PAD
Configuration Examples
The following example shows asynchronous and synchronous terminals using the
X.28/PAD feature of X.25 PSCS to communicate with an X.29 host.
Figure 4–11 shows a simple network map.
Figure 4–11. X.28/PAD Connection to X.29 Host
———————————————————————————————————————
7831 5470–200 4–29

Configuration Examples
Telcon configuration example
4–30
7831 5470–200

Configuration Examples
7831 5470–200 4–31

Configuration Examples
4–32
———————————————————————————————————————
Figure 4–12 shows statement relationships for this configuration.
Figure 4–12. X.28/PAD Statements (DNS)
———————————————————————————————————————
7831 5470–200

4.7 X.29 PAD with Nonconfigured DTEs
Configuration Examples
The following example shows asynchronous terminals using the X.29 PAD feature of
X.25 PSCS to communicate with an OS 2200 host.
Figure 4–13 illustrates this configuration.
Figure 4–13. X.29 PAD Connection to OS 2200 Host (Nonconfigured DTEs)
———————————————————————————————————————
7831 5470–200 4–33

Configuration Examples
CMS configuration example
4–34
———————————————————————————————————————
7831 5470–200

Telcon configuration example
Configuration Examples
7831 5470–200 4–35

Configuration Examples
4–36
———————————————————————————————————————
7831 5470–200

Figure 4–14 shows statement relationships for this configuration.
Configuration Examples
Figure 4–14. X.29 PAD with Nonconfigured DTEs (Statements)
———————————————————————————————————————
7831 5470–200 4–37

Configuration Examples
4.8 X.29 PAD with Configured DTEs and
X25ROUTE Statement
4–38
The following example shows asynchronous terminals using an X.29 PAD
configuration to communicate with an OS 2200 host. DTE and X25ROUTE statements
are used so that only calls from these DTEs are accepted. All other calls are rejected.
Figure 4–15 illustrates this configuration.
Figure 4–15. X.29 PAD Connection to OS 2200 Host (Configured DTEs)
———————————————————————————————————————
7831 5470–200

CMS configuration example
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–39

Configuration Examples
Telcon configuration example
4–40
7831 5470–200

Configuration Examples
———————————————————————————————————————
7831 5470–200 4–41

Configuration Examples
4–42
Figure 4–16 shows statement relationships for this configuration.
Figure 4–16. X.29 PAD with Configured DTEs (Statements)
———————————————————————————————————————
7831 5470–200

4.9 DCP-to-Remote Host Using PLS
Configuration Examples
The following example shows a PLS configuration, which enables an OS 2200
application to use X.25 PSCS services to access a remote host.
Figure 4–17 shows a simple network map.
Figure 4–17. DCP-to-Host Configuration Using PLS
———————————————————————————————————————
7831 5470–200 4–43

Configuration Examples
CMS configuration example
4–44
———————————————————————————————————————
7831 5470–200

Telcon configuration example
Configuration Examples
7831 5470–200 4–45

Configuration Examples
4–46
———————————————————————————————————————
7831 5470–200

Figure 4–18 shows statement relationships for this configuration.
Figure 4–18. DCP-to-Host Using PLS (Statements)
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–47

Configuration Examples
4.10 Two-Node DCE Network
4–48
The following example configures a two-node DCE network with an X.75 interface to
the Telenet network. Figure 4–19 shows a simple network map for this configuration.
Figure 4–19. DCE Network Configuration with an X.75 Interface (DNS)
———————————————————————————————————————
DTE
7831 5470–200

CMS configuration example
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–49

Configuration Examples
Telcon configuration example
4–50
7831 5470–200

Configuration Examples
7831 5470–200 4–51

Configuration Examples
4–52
———————————————————————————————————————
7831 5470–200

Figure 4–20 shows the statement relationships for this configuration.
Figure 4–20. DCE Network (Statements)
Configuration Examples
———————————————————————————————————————
7831 5470–200 4–53

Section 5
Using Network Management Services
(NMS)
This section describes how to use Network Management Services (NMS) to monitor
and control X.25 PSCS facilities. NMS services have been extended to include facilities
that use X.25 PSCS. This section supplements information provided in the DCP Series
Telcon Operations Reference Manual (7831 5728). It covers only those additional NMS
capabilities provided to manage PSCS related facilities.
NMS changes include enhancements to the DOWN, LIST, STAT, TRAC, and UP
commands and the addition of the RECORD and SWITCH commands. Other NMS
commands also monitor and control X.25 PSCS facilities, but do not have PSCS
specific parameters and are not described here. These commands include the CNFG,
ITLN, MOVE, STOP, and STTH commands. You cannot use the STRT and STOP
commands on PDN lines.
Section Topic
5.1 NMS Command Authority Levels
5.2 DOWN — Deactivating a Facility
Format
Parameters
5.3 LIST — Displaying Line Activity
Format
Parameters
5.4 RECORD — Controlling DCE Network Statistics Gathering
Format
Parameters
continued
7831 5470–200 5–1

Using Network Management Services (NMS)
5–2
Section Topic
5.5
5.5.1
5.5.2
5.5.3
STAT — Displaying Status
Format
Parameters
STAT LINE Display
STAT PDTE Display
STAT PTRK Display
5.6 SWITCH — Rerouting Call Packets
Format
Parameters
5.7
5.7.1
5.7.2
TRAC — Message Tracing
TRAC SNAP X25
Format
Parameters
Examples
TRAC SNAP DCEF
Format
Parameters
5.8 UP — Activating a Facility
Format
Parameters
——————————————————————————————————————
7831 5470–200

Using Network Management Services (NMS)
5.1 NMS Command Authority Levels
Telcon requires certain authorization levels to issue NMS commands on facilities
defined for X.25 PSCS. These levels are listed below.
Command Facility Authority
DOWN DTE Node
DOWN Trunk Node
DOWN Line Regional
DOWN Terminal Regional
LIST Line Privileged
RECORD N/A None
STAT DTE None
STAT Trunk None
STAT Line None
STAT Terminal None
SWITCH DTE None
TRAC N/A Privileged
UP DTE Node
UP Trunk Node
UP Line Regional
UP Terminal Regional
——————————————————————————————————————
7831 5470–200 5–3

DOWN
5.2 DOWN — Deactivating a Facility
Format
The NMS DOWN command has been enhanced for X.25 PSCS to deactivate X.25 lines,
terminals, DTEs, and trunks.
——————————————————————————————————————
DOWN
Parameters
5–4
DCP name/netadd
,LINE name/number
,TERM name
,PDTE name/address
,PTRK name
——————————————————————————————————————
DCP=name/netadd
The DCP associated with the facility that is to be deactivated. Refer to the DCP by a PRCSR
statement name or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
LINE=name/number
The X.25 line to deactivate. Refer to this line either by the name or port number specified on a
LINE statement.
7831 5470–200

TERM=name
A terminal to deactivate. Refer to this terminal by the name that identifies it on a TERM
statement.
PDTE=name/address
DOWN
A DTE to deactivate. Refer to this DTE either by the name or address that identifies it on a DTE
statement. You can use the DOWN command on either a configured or nonconfigured DTE.
However, you can deactivate a nonconfigured DTE only if it has established a virtual circuit
connection to the DCP. This connection is then aborted. However, this does not prevent the
nonconfigured DTE from establishing another connection.
PTRK=name
A trunk to deactivate. Refer to this trunk by the name on a TRUNK statement. Specifying this
parameter deactivates the X.25 portion of the trunk only.
——————————————————————————————————————
7831 5470–200 5–5

LIST
5.3 LIST — Displaying Line Activity
Format
Parameters
5–6
The NMS LIST command has been enhanced for X.25 PSCS to provide status
information on X.25 lines.
——————————————————————————————————————
LIST [DCP=name/netadd][,LINE=name/number][,NAME=name/n]
——————————————————————————————————————
DCP=name/netadd
The DCP associated with the facility that is to be deactivated. Refer to the DCP by a PRCSR
statement name or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
LINE=name/number
The X.25 line on which you want status information. You can refer to this line either by the name
or port number that identifies it in configuration. If you do not specify this parameter, a list of all
active lines on this DCP appears.
NAME=name/n
name Any configured X.25 facility.
n The symbol table entry (STE) index of any configured facility.
The command displays a response similar in format to Telcon configured facilities.
——————————————————————————————————————
7831 5470–200

Figure 5–1 is an example of LIST LINE command output.
Figure 5–1. LIST LINE Command Output
1. Specifies that the protocol handler software for this line is X.25 PSCS.
LIST
2. Specifies the PDNGRP associated with this line. The number identified is the DTE
address configured in the PDNGRP statement.
3. Specifies the number of active switched virtual circuits (SVCs) and the maximum
number configured for this line.
4. Specifies the number of active permanent virtual circuits (PVCs) and the
maximum number configured for this line.
5. Specifies the active logical channels for this line.
6. Specifies the virtual circuit types. In this display, all are switched virtual circuits.
7831 5470–200 5–7

LIST
5–8
7. Specifies that these circuits are in a data transfer state. States include the
following:
State Description
CALL REQ PSCS sent a call request packet to the network or DTE device.
CALL IND PSCS received an incoming call packet from the network or DTE device.
DATA TRANS The circuit is in a data transfer state.
CLEAR REQ PSCS sent a clear request packet to the network or DTE device.
CLEAR IND PSCS received a clear indication packet from the network or DTE device.
RESET REQ PSCS sent a reset request packet to the network or DTE device.
RESET IND PSCS received a reset indication packet from the network or DTE device.
CALL COLL PSCS sent a call request packet and has received an incoming call packet
from the network or DTE device (call collision).
READY A permanent virtual circuit that was formerly in a data transfer state, but is
now out of order.
8. Specifies the Level 4 program. Refer to the discussion of the DTETYPE statement
in Section 6, “Using X.25 PSCS Configuration Statements.”
9. Identifies the DTEs communicating over virtual circuits. If no name is present, the
connection is using a nonconfigured circuit.
10. Identifies the addresses of the DTEs using the virtual circuits.
11. Specifies all active terminals on the line. PSCS identifies only terminals attached to
a UTS 4000 Cluster Controller or configured to use the X.29 PAD feature.
——————————————————————————————————————
7831 5470–200

5.4 RECORD — Controlling DCE Network
Statistics Gathering
Format
Parameters
RECORD
The NMS RECORD command enables you to control statistics collection for DCE
networks. Statistics are collected for any virtual circuit connection; however, the DCE
Network feature must be configured to use this command. The statistics collected are
reported through the Telcon CENLOG mechanism. (See the DCP Series Telcon
Message Manual [7436 0728].) A Class 7/Event 1 CENLOG is generated when a virtual
circuit connection is formed or cleared, and whenever the number of data packets
specified on the LOG parameter has occurred.
——————————————————————————————————————
RECORD
DCP name/netadd
,SET ON/OFF
,LOG num
,STAT YES
——————————————————————————————————————
DCP=name/netadd
The DCP associated with the facility that is to be deactivated. Refer to the DCP by a PRCSR
statement name or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
SET=ON|OFF
Starts or stops statistics collection.
7831 5470–200 5–9

RECORD
5–10
LOG=num
The number of data packets between periods of statistic collection.
STAT=YES
Displays statistics collection attributes on the console screen. This display tells you if statistics
collection is on or off and provides the logging frequency number.
——————————————————————————————————————
7831 5470–200

5.5 STAT — Displaying Status
Format
The NMS STAT command has been enhanced to provide status reports on lines
connected to PDNs and X.25 DTEs and trunks.
STAT
——————————————————————————————————————
STAT
Parameters
DCP name/netadd
,LINE name/number
,PDTE name/address
,PTRK name
,TERM name
——————————————————————————————————————
DCP=name/netadd
The DCP associated with the facility that is to be deactivated. Refer to the DCP by a PRCSR
statement name or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
LINE=name/number
A line on which to display status information.
7831 5470–200 5–11

STAT
5–12
PDTE=name/address
A DTE on which to display status information. You can refer to this DTE either by the name or
address that identifies it on a DTE statement.
PTRK=name
A trunk on which to display status. Refer to this trunk by the name that identifies it on a TRUNK
statement.
TERM=name
A terminal to display status information. Refer to this terminal by the name that identifies it on a
TERM statement. X.29 PAD terminals referencing PDNPAD statements and UTS 4000 Cluster
Controller terminals running UTS X.25 software are types known by X.25 PSCS. The status
information format is the same as other terminal types supported by Telcon.
——————————————————————————————————————
7831 5470–200

5.5.1 STAT LINE Display
STAT
Figure 5–2 is an example of STAT LINE command output for a standard X.25 line.
Most fields within the display are the same as for a Telcon line. If you request status
for an ILM-20 line, standard output for a Telcon line appears.
Figure 5–2. STAT LINE Display
1. Specifies that the Data Set Ready signal is present. If DISCONNECTED is
indicated, the Data Set Ready signal is off.
2. Specifies that the protocol handler software for this line is X.25 PSCS.
3. Specifies DTE or DCE, depending on the DTX parameter on the X25DEF
statement.
4. Specifies all active terminals on the line. PSCS identifies only terminals attached to
a UTS 4000 Cluster Controller or configured to use the X.29 PAD feature.
7831 5470–200 5–13

STAT
5–14
5. Specifies that the Level 2 software has established a link level connection with its
peer.
6. Indicates that this line is configured for the Datapac network by the X25DEF
statement.
7. Identifies the following information:
• Number of active switched virtual circuits
• Total number of switched virtual circuits configured by the PDNGRP
statement
• Number of active permanent virtual circuits
• Total number of permanent virtual circuits configured by the PDNGRP
statement
——————————————————————————————————————
7831 5470–200

5.5.2 STAT PDTE Display
Figure 5–3 is an example of STAT PDTE command output.
1. This DTE is enabled.
Figure 5–3. STAT PDTE Display
2. This DTE is associated with the third (0003) PDNGRP statement listed in
configuration.
3. This DTE maintains two logical channels.
STAT
4. PLS is the Level 4 program that uses logical channel 0050. Refer to the discussion
of the DTETYPE statement in Section 6, “Using X.25 PSCS Configuration
Statements.”
7831 5470–200 5–15

STAT
5–16
5. The logical channel is in the data transfer state. Other data states include:
State Description
CALL REQ PSCS sent a call request packet to the network or DTE device.
CALL IND PSCS received an incoming call packet from the network or DTE device.
DATA TRANS The circuit is in the data transfer state.
CLEAR REQ PSCS sent a clear request packet to the network or DTE device.
CLEAR IND PSCS received a clear indication packet from the network or DTE
device.
RESET REQ PSCS sent a reset request packet to the network or DTE device.
RESET IND PSCS received a reset indication packet from the network or DTE
device.
CALL COLL PSCS sent a call request packet and has received an incoming call
packet from the network or DTE device (call collision).
READY A permanent virtual circuit that was formerly in a data transfer state, but
has since become out of order.
BEING ACTIVATED PSCS is processing a virtual circuit establishment. PDNTRUNK (DCP-to-
DCP) layer 4 program only.
ACTIVE The logical channel is in a data transfer state. PDNTRUNK (DCP-to-DCP)
layer 4 program only.
BEING DEACTIVATED PSCS is processing a virtual circuit disconnection. PDNTRUNK (DCP-to-
DCP) layer 4 program only.
NO. OF TRANSPORT
CONNECTIONS=nnnn
NO. OF LOGICAL
SUBCHANNELS=nnnn
PDNUNIS (UTS 4000 Cluster Controller) layer 4 program only. The
virtual circuit is in the data transfer state and nnnn transport connections
are running over the logical channel.
PDNDXA (U Series or PC systems running IS software). The virtual circuit
is in the data transfer state and nnnn logical subchannels are running
over the logical channel.
——————————————————————————————————————
7831 5470–200

5.5.3 STAT PTRK Display
Figure 5–4 is an example of STAT PTRK command output.
Figure 5–4. STAT PTRK Display
STAT
7831 5470–200 5–17

STAT
5–18
1. Specifies that one or more virtual circuits are in the data state. Other possible
states include:
State Description
IDLE The idle trunk circuit timer has expired and all virtual circuits have been
cleared. The higher level entity, such as DNS, perceives the trunk connection
as up.
ENABLED
AND UP
The trunk is not marked down in configuration and X.25 PSCS is attempting to
establish a virtual circuit connection with a peer. The higher level entity, such
as DNS, perceives the trunk connection as up.
DOWN The trunk is marked down in configuration. No virtual circuit connections are
up.
ENABLED
BUT DOWN
INACTIVE
AND DOWN
Although the trunk connection is not marked down in configuration, X.25 PSCS
is making repeated attempts to make a virtual circuit connection with a peer.
The higher level entity perceives the trunk connection as down.
The trunk connection is not marked down in configuration. Virtual circuit
connections have not been established with a peer and X.25 PSCS is not
attempting to establish any connections. The higher level entity perceives the
trunk connection as down.
2. This trunk is associated with the eleventh PDNGRP statement listed in the
configuration.
3. This trunk maintains three logical channels.
4. This trunk is the LEVEL4 protocol using logical channel 0001. This protocol always
controls X.25 trunk connections.
5. The logical channel is in the data transfer state. States include:
State Description
BEING ACTIVATED The logical channel is processing a virtual circuit establishment.
ACTIVE The logical channel is in the data transfer state.
BEING DEACTIVATED The logical channel is processing a virtual circuit disconnection.
——————————————————————————————————————
7831 5470–200

5.6 SWITCH — Rerouting Call Packets
Format
SWITCH
The NMS SWITCH command provides three functions related to rerouting calls on
DCE networks:
• Activates call switching, enabling you to direct packet calls intended for one DTE
to another DTE.
• Enables you to deactivate call switching.
• Displays call switching status on the console screen. This status display lists all
the addresses of DTEs using call switching.
——————————————————————————————————————
SWITCH
Parameters
DCP name/netadd
name1/name2
,DTE
address1/address2
name1
,CANCEL
address1
,STAT YES
ON
,SET
OFF
——————————————————————————————————————
DCP=name/netadd
The DCP that is to issue the SWITCH command. Refer to the DCP by a PRCSR statement name
or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
7831 5470–200 5–19

SWITCH
5–20
DTE=name1/name2
address1/address2
CANCEL=name1
address1
STAT=YES
SET=ON|OFF
name1/name2
The names of DTE statements. Messages intended for name1 are routed to
name2. Using names to switch DTEs must be limited to the same Telcon
processor. You must specify DTE addresses when switching calls across
different Telcon processors (nodes).
address1/address2
DTE addresses. Messages intended for address1 are routed to address2.
name1 Cancels call switching for the DTE identified by this name. The name is the
label on a DTE statement. Issue this command only on DTEs whose calls have
been switched.
address1 Cancels call switching for the DTE identified by this address. Issue this
command only on DTEs whose calls have been switched.
ALL Cancels call switching for all DTEs on this DCP.
Displays call switching status for a DCP on the console screen.
Indicates that call switching is activated or deactivated.
——————————————————————————————————————
7831 5470–200

5.7 TRAC — Message Tracing
TRAC
The NMS TRAC command has been enhanced for X.25 PSCS to pass trace information
to the PSCS trace process.
——————————————————————————————————————
5.7.1 TRAC SNAP X25
Format
The TRAC SNAP X25 command is used to pass X.25 PSCS trace information to the
X.25 PSCS trace process.
——————————————————————————————————————
Parameters
——————————————————————————————————————
SNAP=X25
Activates the tracing mechanism.
TYPE={H,M|L}
Specifies the tracing option:
H The interface to trace
M The item to trace
L Catalogue, open, and close the trace file
If type M or H level of tracing is specified before a DCPOS file has been catalogued using type L,
then the size of the file defaults to 256 blocks. If both H and M are selected, the trace bits you
enabled with the DATA parameter apply to both the interface to trace and the items to trace.
If you specify either M or H, you must also reenter the TRAC command for the other TYPE
option.
7831 5470–200 5–21

TRAC
5–22
FAC=name
Identifies the name of any referenced X25DEF statement for PSCS.
DATA=number
Specifies the trace bits enabled. You must always specify a four-digit number.
Note: 1. There must be a packet exchange or a layer 3/4 platform primitive
exchange to activate the values entered by the TRAC command. An
exchange must take place each time the command is issued. To force an
exchange, issue an NMS down/up command.
2. Tracing does not become active until the interfaces (parameter TYPE=H)
and items (parameter TYPE=M) have been specified using either one or
two TRAC commands containing non-zero DATA parameter values.
DATA Fields for the Interface to Trace (H Parameter Type)
DATA Interface Description ID
0001
0002
0004
0008
0010
0020
0040
0080
0100
*
*
*
*
*
PDNL3 to PDNPP
PDNL3 to PDNCALL
PDNL3 to a level 4
PDNCALL to PDNL3
PDNCALL to a level 4
PDNPP to PDNL3
A level 4 to PDNL3
A level 4 to PDNCALL
Trace facilities
Trace of an error event
Debug reference
CENLOG reference
NMS event
Time expiration
L3L2
L3PC
L3L4
PCL3
PCL4
L2L3
L4L3
L4PC
FAxx
ERnn
DEBG
CNLG
NMS
TIMR
* If a trace is activated, these interfaces are automatically traced and
cannot be selected.
7831 5470–200

DATA Fields for the Items to Trace (M Parameter Type)
DATA Item Description ID
0001
0002
0004
0008
**
Register trace
MCT
Message buffer
ZV$ virtual circuit table
XR$ route table
REGS
MCT
MSG
ZV$T
XR$T
** If a trace is activated, this item is automatically traced at the PDNL3
to PDNCALL (ID=L3PC) interface.
DATA Fields for the L Parameter Type
DATA File Description
0000
size
The cataloged DCPOS trace files are:
X25*ZZ$PDNL3
X25*ZZ$PDNPC
where:
ZZ = Telcon node id (AZ$NODEID)
Close trace file
Catalogue trace file of size given in blocks
TRAC
——————————————————————————————————————
7831 5470–200 5–23

TRAC
Examples
5–24
The following examples detail how to use the TRAC command in X.25 PSCS.
Examples 1 and 2 set all interfaces and all items to be traced. Example 3 explains how
to select specific interfaces and items to trace using the TRAC command.
The CENLOG message indicates that the SNAP processor has received
the command and has set the appropriate values in X.25 PSCS. It does not mean that
the trace itself has been turned on. X.25 PSCS does not activate a trace until one of
the following X.25 CENLOG messages displays on the NMS console:
CENLOG Message Meaning
Trace file size is activated.
Interfaces to be traced are activated.
Items to be traced are activated.
Example 1
Example 1 sets all interfaces and all traceable items with the default file size. Under
normal system conditions, all interfaces and all items are traced. A trace does not end
when the catalog trace file is full; the information at the beginning of the file is
overwritten. Only the last 256 blocks of trace data (the catalogued length of the trace
file) is present in a trace that exceeds the file size.
or
The file size defaults to 256 blocks since TYPE=L was not entered. TYPE=HM sets the
interface and the items to be traced. DATA=number sets all locations and all items to
be traced. NDEF2 is the name of an X25DEF statement in the configuration.
Two CENLOG messages display when the trace is activated:
and . The X.25 line must be active, with
packets received either from the network or from a level 4, for the CENLOG messages
to be received.
Note: There must be a packet exchange or a layer 3/4 platform primitive exchange
to activate the values entered by the TRAC command. An exchange must take
place each time the command is issued. To force an exchange, issue an NMS
down/up command.
7831 5470–200

Example 2
Example 2 sets the file size to 600 blocks, with all interfaces and all traceable items
traced.
or
TRAC
The X.25 line must be active. The CENLOG message
displays when the catalog command is completed. The TRAC command
setting the interface and the items to be traced can then be entered (see Example 1).
Note: There must be a packet exchange or a layer 3/4 platform primitive exchange
to activate the values entered by the TRAC command. An exchange must take
place each time the command is issued. To force an exchange, issue an NMS
down/up command.
Example 3
Example 3 details how the TRAC command traces a specific interface or combination
of interfaces, as well as how the TRAC command is set to trace specific information at
each interface. The DATA field for the TYPE=H parameter is used to trace interfaces;
the DATA field for the TYPE=M parameter is used for identifying specific items to be
traced.
To set the file size to 600 blocks, to trace a specific interface (PDNL3 to PDNPP and
PDNPP to PDNL3), and to trace specific items (registers and the ZV$ table), the
following commands must be issued:
or
The X.25 line must be active.
Note: There must be a packet exchange or a layer 3/4 platform primitive exchange
to activate the values entered by the TRAC command. An exchange must take
place each time the command is issued. To force an exchange, issue an NMS
down/up command.
7831 5470–200 5–25

TRAC
5–26
The CENLOG message displays when the
catalog command has been completed. The TRAC command setting the interface can
then be entered:
or
This command sets the interfaces to be traced (1 = PDNL3 to PDNPP and
20 = PDNPP to PDNL3). The CENLOG message
displays when the interface command has been set. The TRAC command setting the
specific items to be traced (1 = registers and 80 = the ZV$ table) can then be entered:
or
The CENLOG message displays when the TRAC
command tracing specific items has been set. The trace is now active.
To terminate a trace, enter the following:
or
The CENLOG message displays when the termination is
completed. The X.25 line must be active for the termination command to take effect.
Note: There must be a packet exchange or a layer 3/4 platform primitive exchange
to activate the values entered by the TRAC command. An exchange must take
place each time the command is issued. To force an exchange, issue an NMS
down/up command.
——————————————————————————————————————
7831 5470–200

5.7.2 TRAC SNAP DCEF
Format
The TRAC SNAP DCEF command is used to pass DCE Network feature trace
information to the X.25 PSCS trace process.
TRAC
——————————————————————————————————————
or
Parameters
——————————————————————————————————————
SNAP=DCEF
Activates the tracing mechanism.
FAC=name
The name of the EU statement for DCE feature.
DATA=number
The trace bits enabled, or used to stop tracing. You must always specify a four-digit number.
Note: There must be a packet exchange or a layer 3/4 platform primitive exchange
to activate the values entered by the TRAC command. An exchange must take
place each time the command is issued. To force an exchange, issue an NMS
down/up command.
7831 5470–200 5–27

TRAC
5–28
Interface, Item, File Data Options
DATA Description ID
0000
0001
0002
0004
0008
0010
0020
0040
0080
0100
0200
0400
0800
1000
2000
Stop tracing and close the trace file
Connection table entries (DC$)
Configuration table entries (DF$)
Input messages from DTP
Output messages to DTP
Registers
Work area (OW$)
Input messages from PDNL3
Output messages from PDNL3
Input packets from PDNL3
Output packets to PDNL3
Input messages from layer 4
Input packets from layer 4
Output messages to layer 4
Output packets to layer 4
The cataloged trace file is X25*ZZ$PDNET
where:
ZZ = Telcon node id (AZ$NODEID)
The size of each trace file cataloged is 256 blocks (256 bytes per block).
N/A
CONN
CNFG
DTPI
DTPO
REGS
WORK
PDBI
PDBO
PDPI
PDPO
L4BI
L4PI
L4BO
L4PO
——————————————————————————————————————
7831 5470–200

5.8 UP — Activating a Facility
Format
The NMS UP command has been enhanced to activate an X.25 DTE, trunk, line, or
terminal.
——————————————————————————————————————
UP
Parameters
DCP name/netadd
,LINE name
,TERM name
,PDTE name/address
,PTRK name
——————————————————————————————————————
DCP=name/netadd
The DCP associated with the facility that is to be deactivated. Refer to the DCP by a PRCSR
statement name or by a DNS node address. This address has the following parts:
• The subdomain number. The range is 1–65,535, and the default is the local subdomain
number.
• The super cluster number. The range is 1–255, and the default is the local super cluster
number.
• The simple cluster number. The range is 1–255, and the default is the local simple cluster
number.
• The node number. The range is 1–4,095.
If you do not specify this parameter, NMS executes the command on the DCP to which your
terminal is connected.
LINE=name
A line named in the configuration statement to activate.
7831 5470–200 5–29
UP

UP
5–30
TERM=name
A terminal to activate. Refer to this terminal by the name that identifies it on a TERM statement.
PDTE=name/address
A DTE to deactivate. Refer to this DTE either by the name or address that identifies it on a DTE
statement.
PTRK=name
A trunk to activate. Refer to this trunk by the name on a TRUNK statement. Specifying this
parameter activates the X.25 portion of the trunk only.
——————————————————————————————————————
7831 5470–200

Section 6
Using X.25 PSCS Configuration
Statements
This section describes the configuration statements necessary to configure X.25 PSCS.
It provides information on standard Telcon statements that have been modified for
PSCS and on statements created especially for PSCS. Descriptions of modified
statements focus entirely on parameters that affect X.25 PSCS configuration.
Section Topic
6.1 CLSTR — Defining UTS Terminal Clusters
Format
Parameters
Example
6.2
6.2.1
6.2.2
6.3
6.3.1
6.3.2
DTE — Defining Data Terminal Equipment
DTEs on PDNs, the DDN, or Private Networks
Format
Parameters
Examples
DTEs on DCE Networks
Format
Parameters
Examples
DTETYPE — Defining DTE Communication Attributes
DTETYPEs for Standard Packet Networks
Format
Parameters
Examples
DTETYPEs for DCE Networks
Format
Parameters
Example
Online configuration differences
continued
7831 5470–200 6–1

Using X.25 Configuration Statements
6–2
Section Topic
6.4
6.4.1
6.4.2
6.4.3
6.5
6.5.1
6.5.2
EU — Defining X.25 PSCS End Users
EUs for X.28/PAD End Users
Format
Parameters
Examples
EUs for PLS End Users
Format
Parameters
Example
EUs for DCE Network
Format
Parameters
Example
LCLASS — Defining Line Characteristics
LCLASS for Standard Communications Lines
Format
Parameters
Example
LCLASS for ILM-20 Lines
Format
Parameters
Example
6.6 LINE — Defining Physical Communications Lines
Format
Parameters
Examples
6.7
6.7.1
6.7.2
6.7.3
PDNGRP — Defining a Network Connection
PDNGRPs for PDNs and Private Packet Networks
Format
Parameters
Examples
PDNGRPs for the DDN
Format
Parameters
Examples
PDNGRPs for DCE Networks
Format
Parameters
Examples
continued
7831 5470–200

Section Topic
Using X.25 PSCS Configuration Statements
6.8 PDNPAD — Defining Operational Parameters for a PAD
Format
Parameters
Examples
6.9
6.9.1
6.9.2
TERM — Defining a Terminal
Terminals Using the UTS 4000 Cluster Controller
Format
Parameters
Example
Terminals Using the X.29 PAD
Format
Parameters
Example
6.10 X25DEF — Defining Network Characteristics
Format
Parameters
Examples
Online configuration differences
6.11 X25NET — Defining DCE Network Routes
Format
Parameters
Examples
6.12 X25ROUTE — Specifying Routing Precedence
Format
Parameters
Example
Online configuration differences
———————————————————————————————————————
7831 5470–200 6–3

CLSTR
6.1. CLSTR — Defining UTS Terminal Clusters
Format
Parameters
Example
6–4
The CLSTR statement defines UTS 4000 terminal clusters. It is a standard Telcon
statement that has been modified for X.25 PSCS, enabling you to define UTS 4000
terminal clusters as DTEs. Each UTS 4000 requires a CLSTR statement.
———————————————————————————————————————
———————————————————————————————————————
GROUP=parnt
Specifies a GROUP statement. Although X.25 PSCS does not reference the GROUP parameter,
Telcon requires it. To satisfy this requirement, reference any valid GROUP statement that does
not reference a LINE statement.
DTE=dte
Specifies a DTE statement. This parameter is required for UTS 4000 Cluster Controllers that will
function as remote DTEs.
———————————————————————————————————————
In the following example, a UTS 4000 Cluster Controller is defined as a DTE.
———————————————————————————————————————
7831 5470–200

6.2. DTE — Defining Data Terminal Equipment
DTE
The DTE statement defines data terminal equipment (DTE) that is either attached to a
network or directly attached to a DCP. A DTE is a computer or terminal that
communicates directly with a network switch, called data circuit-terminating
equipment (DCE). A single computer can function as one or several DTEs, since it can
be connected to different networks simultaneously or have multiple connections to the
same network.
X.25 PSCS enables communications with two types of DTEs: configured and
nonconfigured. A configured DTE is one defined in the DCP configuration file. You
can define up to 5000 DTEs in your DCP configuration file. The following devices must
be defined as configured DTEs:
• Other DCPs or U Series systems running the DNS protocol
• Devices using the DCE Network feature
• UTS 4000 Cluster Controllers
• Unisys workstations or U Series running DCA protocols
• Devices requiring permanent virtual circuits
• Foreign systems running SNA applications
• DTEs using the packet layer services (PLS) interface
U Series systems and foreign systems running TCP/IP or OSI applications can function
as configured or nonconfigured DTEs. The advantage of configuring DTEs is that you
can use them to filter incoming call packets and control their routing. In conjunction
with the X25ROUTE statement, you can configure X.25 PSCS to only accept incoming
calls from DTEs that are configured. This provides a filtering mechanism that requires
no layer 4 program action. The incoming call is routed to the configured layer 4
program specified on the LEVEL4 parameter of the associated DTETYPE statement.
The disadvantage of configured DTEs is that more overhead is incurred during
incoming call packet processing, and during the one-time initialization of X.25 PSCS.
Section 6.2.1 explains how to use the DTE statement in PDN, the DDN, and private
packet network environments. Section 6.2.2 explains how to use the statement in a
DCE Network environment. A single DCP can function in both environments
simultaneously. In addition, this discussion includes information on online
configuration, which explains how to implement online changes to the DTE statement.
———————————————————————————————————————
7831 5470–200 6–5

DTE
6.2.1. DTEs on PDNs, the DDN, or Private Networks
Format
Parameters
6–6
This section explains how to use the DTE statement to configure a DCP — acting as a
DTE itself — to communicate with other DTEs attached to PDNs, private packet
networks, or the DDN.
———————————————————————————————————————
———————————————————————————————————————
DTETYPE=dname
A DTETYPE statement. A DTE must reference a DTETYPE statement to identify a LEVEL4
protocol implementation, define maximum packet and window sizes, and define connection retry
parameter values.
PDNGRP=parnt
A PDNGRP statement. A DTE must reference a PDNGRP statement to identify logical channel
ranges and virtual circuit types for connections with this DTE, and to identify network operating
characteristics.
DTEADR='addr'
The address of the remote DTE. You must specify an address for switched virtual circuits or if
the layer 4 program is Packet Layer Services (PLS). A DTE must have an address and the
address must be unique unless you specify the FIXED option. The DTE address is assigned by
the network, can be a maximum of 15 digits, and must be enclosed in apostrophes.
TRUNK=(tname[,type])
tname A TRUNK statement. Use this parameter when the remote DTE is another DCP or a
U Series system running DNS. If you reference a TRUNK statement here, specify
LEVEL4=PDNTRUNK on the associated DTETYPE statement.
type The kind of trunk. Use MIXED if this trunk consists of a UDLC and PDN connections.
Use PDN if it consists of PDN connections only. PDN is the default.
7831 5470–200

DCATS=sname
A DCATS statement. Use this parameter when the remote DTE is a Unisys workstation or
U Series system running DCA protocols. If you reference a DCATS statement here, specify a
LEVEL4=PDNDXA on the associated DTETYPE statement.
PERMVC=(flc,llc)
Specifies that the DTE uses permanent virtual circuits.
DTE
flc Specifies the first logical channel of a permanent virtual circuit. This number must fall
within the range of channel numbers specified on the VCGRP parameter of the PDNGRP
statement, and it must be equal to or less than the value specified for the last logical
channel.
llc Specifies the last logical channel of a permanent virtual circuit. This number must fall
within the range of channel numbers specified on the VCGRP parameter of the PDNGRP
statement, and it must be equal to or greater than the value specified for the first
logical channel.
Ensure that the ranges specified for one PERMVC parameter do not overlap the ranges specified
for other PERMVC parameters of DTE statements having the same PDNGRP parent.
OPTIONS=(opt1,opt2, ...)
Specifies the options allowed for this DTE.
Options:
ABBRVADR Specifies that the DTE address is abbreviated, that is, partially specified, starting
with the most significant address digits. Using this option enables you to configure
many DTEs with the same DTE statement. This option is available for both
outgoing and incoming calls. On outgoing calls, X.25 PSCS uses the partial
address to determine the correct line on which to place a call request. On
incoming calls, X.25 PSCS uses it to determine the correct Level 4 program to
which to route calls. Do not use this option when the LEVEL4 parameter on the
associated DTETYPE statement is PDNTRUNK, PDNUNIS, PDNX28, PLS, or
PDNDXA, or when this DTE statement defines permanent virtual circuits. By default,
this option is only used during outgoing call processing. If you want to use it for
incoming calls only, specify the CALLING option. If you want to use it for both
outgoing and incoming calls, specify CALLED and CALLING. For more information,
see "Configuring Partial DTE Addresses" in Section 2.
7831 5470–200 6–7

DTE
6–8
CALLED Specifies that X.25 PSCS processes this DTE statement on outgoing calls only.
This DTE statement is ignored during incoming call processing. For more
information, see "Configuring the CALLED and CALLING Options" in Section 2.
CALLING Specifies that X.25 PSCS processes this DTE statement on incoming calls only.
This DTE statement will be ignored during outgoing call processing. For more
information, see "Configuring the CALLED and CALLING Options" in Section 2.
Unless using the ABBRVADR option, selecting both the CALLED and CALLING
options has the same effect as selecting neither.
FASTSL Specifies the fast select feature for calls to this DTE, enabling call request packets
and clear indication packets to carry up to 128 octets of user data. If you do not
specify this option, the following occurs:
• Call request packets are limited to 16 octets of user data.
• If a Level 4 program requests an outgoing fast select facility, X.25 PSCS
sends the user data after the call has been established.
• If a Level 4 program requests the fast select with restricted response option
for a call request, X.25 PSCS accepts the subsequent call connected packet.
FIXED Specifies that calls to and from this DTE must go through the PDNGRP (network
connection) specified. If you do not specify this option, calls to this DTE are routed
through the least busy PDNGRP (line) and calls from this DTE are accepted on any
available line.
FLOWC Specifies that call request packets to this DTE require that the flow control
negotiation facility be encoded and that the level 3 window and packet sizes
specified on the associated DTETYPE statement serve as the desired facility
values. This ensures that X.25 PSCS and the network node agree to the flow
control values being used for virtual circuit connections. If you do not specify this
option, the level 3 window and packet sizes default to the values specified on the
associated DTETYPE statement (it is assumed that the network is using these
values for virtual circuits to this DTE).
RPOA Specifies that call request packets to this DTE be encoded with the RPOA facility
option. Use this option with the RPOA parameter on this DTE statement.
RRVCHG Specifies that calls to this DTE request reverse charging.
RVCHG Specifies that X.25 PSCS accept calls from this DTE requesting reverse charging.
If you do not specify this option and an incoming call packet is encoded for a
reverse charging facility, X.25 PSCS automatically clears the call.
THRUCLAS Specifies that call request packets to this DTE use the throughput class
assignment facility option. Use this option with the THRUCLAS parameter on the
associated DTETYPE statement.
TRANDLY Specifies that call request packets to this DTE encode the facility code for the
transit delay selection. Use this parameter in conjunction with the TRDELAY
parameter on this DTE statement and option 31 on the L3OPT parameter of the
associated X25DEF statement.
7831 5470–200

RPOA=dnic
Specifies the data network identification code number (DNIC) that is encoded in the optional
RPOA facility field. This identifies an intermediate network through which the connection passes
before reaching this DTE. The number must be specified as four hexadecimal digits (X'nnnn').
Use this parameter with the OPTIONS=RPOA parameter.
TRDELAY=tran
Specifies the transit delay time. Specify a time between 1 and 65,535 milliseconds. Use this
parameter with the OPTIONS=TRANDLY parameter on this statement and option 31 on the
L3OPT parameter of the associated X25DEF statement.
CUG=(YES|NO,'cugn')
YES|NO Specifies whether the DTE is a member of a closed user group (CUG).
'cugn' Specifies a two-digit CUG number, which defines the group to which the DTE belongs.
Enclose this number in single quotation marks. See your site administrator for this
number. If the default is selected, the CUG number is not included.
Default
NO is the default.
STATUS=DOWN|UP
Default
Specifies the state in which the DTE is configured, up or down.
UP is the default.
DTE
———————————————————————————————————————
7831 5470–200 6–9

DTE
Examples
6–10
Example 1
Example 1 defines a PDN trunk, that is a DCP-to-DCP connection across a PDN. The
remote DCP functions as a DTE. The DTE statement references a TRUNK statement
on the TRUNK parameter, which also specifies PDN. The associated DTETYPE
statement specifies LEVEL4=PDNTRUNK.
Example 2
Example 2 is similar to Example 1, except it defines a mixed trunk. That is, it defines
both a PDN and a UDLC connection, which means the TRUNK parameter specifies
MIXED.
Example 3
Example 3 defines another DCP-to-DCP trunk, this time specifying permanent virtual
circuits. The logical channel numbers defined on the PERMVC parameter must fall
within the range specified on the VCGRP parameter of the associated PDNGRP
statement.
Example 4
Example 4 defines a DCP-to-U Series system connection. The U Series system is
running DCA protocols, so the DTE statement references a DCATS statement. The
associated DTETYPE statement specifies LEVEL4=PDNDXA. It also specifies that calls
from this DTE requesting reverse charging be accepted and assigns this DTE to a
closed user group.
———————————————————————————————————————
7831 5470–200

6.2.2. DTEs on DCE Networks
Format
Parameters
DTE
This subsection explains how to use the DTE statement to configure the DCE network
for communications with directly attached DTEs (DADs).
———————————————————————————————————————
———————————————————————————————————————
DTEADR='addr'
Specifies a DTE address. You must assign an address to each DTE. The addresses assigned
must conform to the following rules:
• Addresses must be 6 to 15 digits.
• The first four digits specify the data network interchange code (DNIC), which identifies the
network to which a called DTE is attached. The ITU/TSS has assigned DNICs for all public
data networks and published these assignments in ITU/TSS Recommendation X.121. You
can assign any four–digit number to the DCE network as long as it has not been assigned to
a PDN to which one of the DCE Network DCPs is attached. This number appears on the
DNICID parameter of the X25NET statement.
• The next one to four digits specify the DCE node number. DTEs configured on the same
DCP must have a common node number. This number appears on the DESTID parameter of
the X25NET statement.
• If you are not configuring a DTE for a hunt group, use the remaining digits to define a DTE
identifier. You can use the same DTE identifier for DTEs on different DCEs, since the DCE
node number portion of the address will make the complete address unique. If you provide a
hunt group address here, you must define the DTE as part of a hunt group by specifying
OPTIONS=HGROUP. For more information on assigning hunt group addresses, see
"Configuring DTE Hunt Groups" in Section 3.
DTETYPE=dname
Specifies a DTETYPE statement. A DTE statement must reference a DTETYPE statement to
define a LEVEL4 protocol and specify maximum packet and window sizes. To use the DCE
Network feature, the DTETYPE referenced must specify LEVEL4=PDNNET. To specify an internal
DTE, use one of the Level 4 programs listed in the DTETYPE statement description covered later
in this section.
7831 5470–200 6–11

DTE
6–12
PDNGRP=parnt
Specifies a PDNGRP statement. A DTE statement must reference a PDNGRP statement to identify
logical channel ranges and virtual circuit types for connections with this DTE. For DCE Network
configurations, the referenced PDNGRP must specify OPTIONS=DAD.
DCATS=sname
Specifies a DCATS statement. Use this parameter when the DTE is a Unisys workstation or U
Series system running DCA protocols. See Section 3.2.4, "Configuring an Internal DTE for U
Series or IS–PC DTEs Running with the TS/TN Protocol."
OPTIONS=(opt1,opt2,...)
Specifies the options allowed for this DAD.
Options:
ABBRVADR Specifies that the DTE address is abbreviated, that is, partially specified, starting
with the most significant address digits. Using this option enables you to configure
subaddressing facilities, enabling a DTE to pass additional address digits.
ACKDATA Specifies end-to-end data assurance for this DTE on all its connections to peer
DTEs. DTEs may obtain data assurance on a per call basis by setting the D-bit in
call request or call accept packets.
FASTSLA Specifies that this DTE accepts call requests with the fast select facility present. If
you do not specify this option, call requests destined for this DTE with the fast
select facility are cleared by the DCE Network feature.
FLOWC Specifies that call request packets to this DTE require that the flow control
negotiation facility be encoded and that the level 3 window and packet sizes
specified on the associated DTETYPE statement serve as the initial maximum
facility values. The DAD may subsequently negotiate lower values. If you do not
specify this option, the level 3 window and packet sizes default to the values
specified on the associated DTETYPE statement.
HGROUP Specifies that this DTE is a member of a hunt group. If you configure this feature,
the DTEADR parameter must follow the addressing conventions for hunt groups.
For more information on configuring hunt groups, see "Configuring DTE Hunt
Groups" in Section 3.
NOCHG Specifies that this DTE does not accept reverse charges on calls destined for this
DTE and requests reverse charging on all calls it initiates.
7831 5470–200

Examples
DCECUG=(opt,a[,b][,c][,d])
DTE
Defines this DTE as a member of a closed user group (CUG) and specifies CUG related options:
ALLOWI Specifies that this DTE accepts calls originating outside its closed user group.
ALLOWO Specifies that this DTE makes calls to devices outside its closed user group.
ALLOWIO Specifies that this DTE makes and receives calls to and from devices outside its
closed user group.
CLOSED Specifies that this DTE does not make or receive calls to or from DTEs outside the
closed user group.
STATUS=DOWN|UP
Specifies the state in which the DTE is configured, up or down.
Default
UP is the default.
———————————————————————————————————————
Example 1
Example 1 defines a DTE connection to a DCE network. There are no special
parameters on the DTE statement, but the associated DTETYPE statement specifies
LEVEL4=PDNNET.
Example 2
Example 2 is similar to Example 1 except it specifies that the DTE is a member of
three closed user groups and that the DTE will not accept calls from or make calls to
devices outside the CUG.
7831 5470–200 6–13

DTE
Example 3
Example 3 is similar to Example 2 except it specifies the fast select option.
———————————————————————————————————————
Online configuration differences
6–14
1. Online configuration changes to DTEADR, CUG, RPOA, OPTIONS, and PDNGRP parameters
take effect after issuing the DOWN PDTE and then UP PDTE commands. Online configuration
changes to the DCECUG parameter take effect immediately.
2. In most cases, online changes to the DTETYPE parameter take effect after issuing the DOWN
PDTE and UP PDTE commands. However, when you change to or from a DTETYPE statement
that specifies a UTS 4000 or TRUNK in the LEVEL4 parameter, you must restart Telcon
before the change takes effect.
3. To free a DTE from association with a CUG, specify DCECUG=NONE.
4. All other online changes take effect only after you restart Telcon.
5. To clear all options, enter the command: OPTIONS=NONE.
6. To remove a DTE from being configured for permanent virtual circuits, enter PERMVC=NONE.
7. To remove the DTE address defined for a DTE, enter DTEADR=NONE.
———————————————————————————————————————
7831 5470–200

6.3. DTETYPE — Defining DTE Communication
Attributes
DTETYPE
The DTETYPE statement defines certain communication attributes between the DCP
and a DTE or network. Specifically, it defines the following:
• The Level 4 program on the DCP to which calls from a DTE are routed
• The maximum number of switched virtual circuits (SVCs) assigned to a
DCP-to-DCP or a DCP-to-U Series system (running DNS) trunk
• Connection retry parameters
• The maximum size of input and output packets
• The maximum number of unacknowledged packets that can be outstanding
• The throughput class assignment facility code that the DCP includes in call request
packets sent to a DTE
Both the network and the Level 4 program can adjust these values dynamically.
DTETYPEs do not reference other statements but are referenced by DTE, PDNGRP,
and X25DEF statements.
———————————————————————————————————————
7831 5470–200 6–15

DTETYPE
6.3.1. DTETYPEs for Standard Packet Networks
Format
Parameters
6–16
This section explains how to use the DTETYPE statement to configure the DCP for
attachment to a PDN, the DDN, or a private packet network.
———————————————————————————————————————
———————————————————————————————————————
LEVEL4=(type[,mxsvc,ncalls,tcalls,tidle,diag])
type Specifies the Level 4 program to which X.25 PSCS routes incoming calls based on the
call packet's calling DTE address. This parameter is required when a DTE statement
references the DTETYPE. It is not required when a PDNGRP or X25DEF statement
references the DTETYPE to define flow control parameters. The following are valid Level
4 programs:
IPOSI Specifies the OSITS internet protocol component of the OSITS program
product, which must be installed to use this option. Use this option for
connectionless-network service.
TPOSI Specifies the OSITS transport service of the OSITS program product, which
must be installed to use this option. Use this option for connection-oriented
network service.
TPCCITT
Specifies the ITU/TSS-defined OSITS transport service component of the
OSITS program product, which must be installed to use this option.
IPTCP Specifies the TCP-IP Stack internet protocol. The TCP-IP Stack program
product must be installed to use this option.
PDNTRUNK
Specifies DCP-to-DCP or DCP-to-U Series system (running DNS) trunk pairing. If
you specify this Level 4 program, specify the TRUNK parameter on the
associated DTE statement.
PDNUNIS
Specifies UTS 4000 cluster-to-DCP pairing.
7831 5470–200

X29PAD
Specifies an X.29 network PAD-to-DCP pairing.
PDNX28
Specifies the X.28/PAD-to-X.29 host pairing.
DTETYPE
PDNDXA
Specifies an X.25 connected PC or U Series system running DCA software. If
you specify this Level 4 program, specify the DCATS parameter on the
associated DTE statements.
PDNNPID
Specifies a local implementation of a network protocol.
PDNIPID
Specifies a local implementation of an international protocol.
PDNUPID
Specifies a local implementation of a user-defined protocol.
PLS Specifies the packet layer services (PLS) host interface software.
VIDEOTEX
Specifies the Videotex program product, which must be installed to use this
option.
AIRNET Specifies the AIR/net program product, which must be installed to use this
option.
TGNPSI Specifies the Transmission Group NPSI Connection interface for the SNA/net
program product, which must be installed to use this option.
BFNPSI Specifies the Boundary Function NPSI Connection interface for the SNA/net
program product, which must be installed to use this option.
CORPNET
Specifies the CORP/net program product, which must be installed to use this
option. Use this option to connect UTS and Poll Select terminals attached to
the DCP to the A Series and to connect terminals attached to the A Series to
the OS 2200.
mxsvc An option when you specify LEVEL4=PDNTRUNK. It specifies the maximum number of
switched virtual circuits a trunk uses. The default is 1. The range is between 1 and the
maximum specified in the SVC parameter on the associated PDNGRP statement.
7831 5470–200 6–17

DTETYPE
6–18
The following four parameter options are available when you specify LEVEL4=PDNTRUNK and you
want to use the Idle Trunk Circuit feature. This feature allows you to control how long inactive
trunk circuits remain connected, and minimize the overhead incurred when establishing or
reestablishing the trunk circuit connections.
ncalls Specifies how many attempts to make to reestablish a virtual circuit connection that has
been cleared because of inactivity. Specify between 0 and 255 attempts. If you do not
specify a value or if you specify 0, X.25 PSCS will attempt to reestablish a circuit until
successful.
tcalls Specifies the amount of time between attempts to reestablish a virtual circuit
connection that has been cleared because of inactivity. Specify between 0 and 65,535
seconds. If you do not specify a value or if you specify 0, 60 seconds is used.
tidle Specifies the amount of time between transmission of network data units (NDUs) before
a circuit is cleared. Specify between 0 and 65,535 seconds. If you do not specify a
value or if you specify 0, X.25 PSCS does not automatically shut down the circuit.
diag Specifies a diagnostic code that indicates that a trunk is in an idle state. When the peer
trunk implementation on the remote DCP or U Series system (running DNS) enters an
idle state, it should encode this value in a clear or reset packet, indicating an idle state,
not an unrecoverable error. Specify a value from 1 to 255. The default is 136.
You can use the following two options when you specify LEVEL4=PDNDXA and you want to
minimize error recovery overhead whenever the DTE is a Unisys PC running IS–PC software (DCA
over TS/TN). When a virtual circuit connection is abnormally terminated by the Unisys PC, X.25
PSCS attempts to reestablish the virtual circuit connection according to these option settings.
Note that the AUTORC=YES parameter option must be specified on the DCATS statement
referenced by this DTE and on the DCATS statement defined for the OS 2200 host.
ncalls Specifies how many attempts to make to reestablish a virtual circuit connection that has
been abnormally cleared by a Unisys PC running the IS–PC (DCA) software. Specify
between 0 and 65,535 attempts. If you do not specify a value or if you specify 0, X.25
PSCS attempts to reestablish a circuit until successful.
tcalls Specifies the time interval in seconds before X.25 PSCS attempts to reestablish a
connection to the Unisys PC. Specify between 0 and 30 seconds. If you do not specify
a value or if you specify 0, 30 seconds is used.
7831 5470–200

PAKSIZ=(ipps[,opps])
DTETYPE
Specifies the size of input and output packets. These values represent the maximum number of
octets per packet used on this DCP's connection to the PDN. Make sure that the network
supports the size you specify. X.25 PSCS supports the following sizes: 16, 32, 64, 128, 256,
512, 1024, 2048, and 4096.
Default
The default input size is 128 octets. The default output size is the value specified for the
input size.
WINSIZ=(ipws[,opws])
Specifies the input and output packet level window for this DCP's connection to a PDN.
Default
The default input size is 2 and the range is between 1 and 7. The default output size is the
value specified for the input size.
THRUCLAS=tclas
Specifies the throughput class assignment facility code that is encoded in call request
packets for DTEs associated with this DTETYPE statement. The permissible values are listed
in Table 6–1.
If you specify a THRUCLAS parameter value, that value will also be used to negotiate
(downward) any throughput class facility value received in an incoming network call packet.
———————————————————————————————————————
7831 5470–200 6–19

DTETYPE
6–20
Table 6–1. Throughput Class Assignment Facility Codes
3
4
5
6
7
8
9
10 (Default)
11
12
13
Code Rate (bps)
75
150
300
600
1,200
2,400
4,800
9,600
19,200
48,000
64,000
———————————————————————————————————————
7831 5470–200

Examples
Example 1
DTETYPE
Example 1 defines a PDN trunk, that is, a DCP-to-DCP connection. It could also be a
DCP-to-U Series system connection if the U Series system is running DNS. The
DTETYPE statement specifies LEVEL4=PDNTRUNK and the associated DTE
statement references a TRUNK statement on the TRUNK parameter.
Example 2
Example 2 is similar to Example 1, except it specifies that the trunk can have a
maximum of ten active virtual circuits.
Example 3
Example 3 is similar to Example 2, except it specifies the ncalls and tidle values as
well. It specifies that 20 attempts should be made to reestablish a cleared circuit and
that 100 seconds must pass between transmissions of network data units (NDUs)
before a circuit is cleared. Since the tcalls value is not specified, commas reserve its
place.
7831 5470–200 6–21

DTETYPE
6–22
Example 4
Example 4 defines a DCP-to-U Series system connection. The U Series system is
running DCA protocols, so the DTETYPE statement specifies LEVEL4=PDNDXA. The
associated DTE statement references a DCATS statement.
Example 5
Example 5 defines a UTS 4000 Cluster Controller as a DTE. The DTETYPE specifies
LEVEL4=PDNUNIS, maximum input and output packet sizes of 256 octets, and a
window size of 4.
———————————————————————————————————————
7831 5470–200

6.3.2. DTETYPEs for DCE Networks
Format
Parameters
This section explains how to use the DTETYPE statement in a DCE network.
DTETYPE
———————————————————————————————————————
———————————————————————————————————————
LEVEL4=PDNNET
Specifies PDNNET as the LEVEL4 protocol type. You must specify PDNNET on this parameter. To
specify internal DTEs on a DCE network, use the Level 4 programs defined for DTETYPEs for
standard packet networks.
PAKSIZ=(ipps[,opps])
Specifies the maximum size of input and output packets for this DTE-DCE connection. The DCE
network supports the following sizes: 16, 32, 64, 128, 256, 512, 1,024, 2,048, and 4,096
octets.
Default
The default input size is 128 octets. The default output size is the input size.
WINSIZ=(ipws[,opws])
Specifies the input and output packet level window for DTE-DCE connection.
Default
The default is input window is 2 and the range is between 1 and 7. The default output size is
the input size.
———————————————————————————————————————
7831 5470–200 6–23

DTETYPE
Example
The following example defines a DCE Network DTE. The DTETYPE statement
specifies LEVEL4=PDNNET.
———————————————————————————————————————
Online configuration differences
6–24
1. When a DTETYPE statement specifies a UTS 4000 or PDNTRUNK Level 4 program, you must
restart Telcon for online configuration changes to take effect. In all other cases, simply issue
the NMS DOWN PDTE and then the UP PDTE commands.
2. If the facility changed is referenced from a PDNGRP or X25DEF statement, first issue the
NMS DOWN LINE and then UP LINE commands on the line connecting the facility to a PDN.
3. If you delete a DTETYPE statement from configuration, you must delete all DTE statements
that reference it or modify the DTE statements to reference another DTETYPE statement.
———————————————————————————————————————
7831 5470–200

6.4. EU — Defining X.25 PSCS End Users
EUs are standard Telcon statements that have been modified for X.25 PSCS. They
define programs that process data received from terminals and other programs. You
use a separate statement to configure each end user program for each processor in the
network. This discussion has been divided into three formats, corresponding to the
three ways X.25 PSCS uses the statement. These are:
• EUs for X.28/PAD end users
• EUs for packet layer services (PLS) end users
• EUs for DCE Network end users
———————————————————————————————————————
6.4.1. EUs for X.28/PAD End Users
Format
Parameters
This section explains how to use the EU statement to configure X.28/PAD end users.
This statement is required to configure a DCP to provide packet
assembler/disassembler (PAD) functionality. It associates an external end user name
(XEU) with a PDN. Each network for which you want to configure a PAD requires a
separate EU statement. You must also use a separate EU for terminals that operate in
a character-at-a-time or buffered character data mode.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=prcsr
Specifies the PRCSR statement on which X.25 PSCS is configured.
TYPE=X28PAD
Specifies that this end user is an X.28/PAD.
NETWORK=netid
Specifies a PDN name. Table 6–2 lists the mnemonics to use here. You cannot use this
parameter unless you specify the NETWORK parameter on the associated X25DEF statement.
7831 5470–200 6–25
EU

EU
6–26
X25DEF=x25type
Specifies an X25DEF statement. If you define a connection to a private network, that is, one for
which there is no mnemonic listed in Table 6–2, you must use the X25DEF parameter.
EUPRCSR=(prcsr,dpp)
Specify this parameter for asynchronous terminals that operate in a character-at-a-mode protocol.
This type of operation allows each character that is entered on the terminal to be forwarded to
the X.29 host. Do not specify this parameter for asynchronous terminals operating in a buffered
character mode (that is, text characters are not forwarded until a carriage return character is
entered). You must not specify this mode for synchronous terminals.
prcsr Specifies the PRCSR statement on which X.25 PSCS is configured.
dpp Specify sxdpp to indicate a character mode.
Note: 1. If this configuration defines a connection to only one network, neither
the NETWORK or the X25DEF parameter is required.
2. Do not specify both the NETWORK and the X25DEF parameter.
3. If all X25DEF statements in this configuration use the same network
parameter name, then use the NETWORK parameters.
———————————————————————————————————————
7831 5470–200

Accunet (USA)
Arpac (Argentina)
Austpac (Australia)
Table 6–2. Network Names and Mnemonics
Network Name Mnemonic (NETWORK=netid)
BX.25 (USA, private operator)
Datapac (Canada)
Datex (Sweden)
Datex–P 1980 (Austria and Germany)
DCS (Belgium)
DDX (NTT Japan)
Defense Data Network (USA)
DN1 (Netherlands)
Euronet
Iberpac (Spain)
Itapac (Italy)
Mexpac (Mexico)
NOPN (Norway)
NPDN (Finland)
PSCSNET
PSS (United Kingdom)
Renpac
SITA (France)
Telenet (USA)
Telepac (Switzerland)
Telepacp (Portugal)
Transpac (France)
ACCUNET
ARPAC
AUSTPAC
BX25
DATAPAC
DATEX
DATEXPA
DCS
DDXP
DDNX25
DN1
EURONET
IBERPAC
ITAPAC
MEXPAC
NOPN
NPDN
PSCSNET
PSS
RENPAC
SITA
TELENET
TELEPAC
TELEPACP
TRANSPAC
7831 5470–200 6–27
EU

EU
Examples
6–28
Example 1
Example 1 defines a PAD for asynchronous terminals operating in a character mode to
an X.29 host. The X.29 host is accessed through the Telenet network. The EU
statement specifies TYPE=X28PAD. The EUPRCSR parameter specifies SXDPP for the
character-at-a-time mode, as does the DPP parameter on the XEU statement.
Example 2
Example 2 defines a PAD for either asynchronous or synchronous terminals accessing
an X.29 host through the Telenet network. The XEU that references the EU specifies
DPP=INT1, which presents characters entered from the terminal in a buffered mode.
Since INT1 is the default protocol on the EU statement's EUPRCSR parameter, it does
not have to be specified. Data messages entered from the terminal can only be sent to
the X.29 host in a buffered character mode.
Example 3
Example 3 combines the two terminal operating modes from Examples 1 and 2.
7831 5470–200

Example 4
Example 4 provides the same terminal operating modes to the DN1 network as well as
to the Telenet network as shown in Example 3. XEU and EU statement pairs can be
repeated for defining access to more than one network and for defining the two
terminal operating modes.
Example 5
Unlike the previous examples, Example 5 uses the X25DEF parameter because the
associated X25DEF statement defines a private network.
———————————————————————————————————————
7831 5470–200 6–29
EU

EU
6.4.2. EUs for PLS End Users
Format
Parameters
6–30
This subsection explains how to use the EU statement to configure PLS end users. The
EU statement associates a host DTP connection with a remote DTE. You must
configure an EU for each DTE requiring this DTP association.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=prcsr
Specifies the PRCSR statement on which X.25 PSCS is configured.
TYPE=PLSTSU
Specifies PLS software as an end user.
USERSTX1=dte
Specifies the name of a DTE statement, which defines the DTE that will use the PLS interface.
USERSTX2=xeu
Specifies the name of an XEU statement that enables a host GASIF interface.
———————————————————————————————————————
7831 5470–200

Example
The following example defines PLS as an end user and associates a DTE with a host
DTP connection. The EU statement specifies TYPE=PLSTSU and references XEU and
DTE statements.
———————————————————————————————————————
7831 5470–200 6–31
EU

EU
6.4.3. EUs for DCE Network
Format
Parameters
6–32
This section explains how to use the EU statement to configure a DCE Network end
user. DCE Network requires one EU statement for each DCP functioning as a DCE.
DCPs that function as routing nodes only do not require a DCE Network EU.
The DCE Network EU associates a DCE node address with a particular DCP through
the PRCSR parameter.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=prcsr
The PRCSR statement that defines the DCP on which DCE Network software runs.
TYPE=DCPNET
Specifies DCE Network software as an end user.
DCENODE='nodeaddr'
Specifies a DCE node address, which is a subset of a DTE address. The DCE node address must
be between five and eight digits and must be enclosed in quotation marks. It consists of the
following:
• A data network identifier code (DNIC), which is a four-digit number that identifies the
network. The ITU/TSS assigns DNICs to public data networks (PDNs). If one or more of the
DCPs in your network connects to a PDN, make sure the DNIC is not the same as the
PDN's.
• A node number, which consists of one to four digits.
———————————————————————————————————————
7831 5470–200

Example
The following example shows an EU statement defining DCE Network software as an
end user and specifying a DCE node address on the DCENODE parameter. Since the
DNIC portion of the node address must be exactly four digits, the node number in this
example is 001.
———————————————————————————————————————
7831 5470–200 6–33
EU

LCLASS
6.5. LCLASS — Defining Line Characteristics
The LCLASS statement defines classes of communications lines, specifying attributes
such as the line speed and the protocol that controls the line. This statement has been
modified for X.25 PSCS, enabling you to specify an X.25 line protocol handler for the
X.21, X.21 bis, and V.35 line modules or a LAPB implementation for an Intelligent Line
Module-20 (ILM-20).
———————————————————————————————————————
6.5.1. LCLASS For Standard Communications Lines
Format
Parameters
Example
6–34
This section explains how to configure the X.25 protocol handler for the X.21, X.21 bis,
and V.35 lines.
———————————————————————————————————————
———————————————————————————————————————
LPH=X25PKT
The X.25 line protocol handler for this line. Use this value for X.21, X.21 bis, and V.35 lines.
OPTIONS=(DIR,SYFD)
A direct, synchronous, full-duplex line, which the X.25 protocol requires.
SPEED=speed
The line speed for lines referencing this LCLASS statement. For X.21 and X.21 bis lines, the
maximum line speed is 19,200 bits-per-second (bps). For V.35 lines, the maximum speed is
65,000 bps.
———————————————————————————————————————
The following example defines a line class, specifying an X.25 protocol handler and a
direct, synchronous, full-duplex line running at 9,600 bps.
———————————————————————————————————————
7831 5470–200

6.5.2. LCLASS For ILM-20 Lines
Format
Parameters
Example
LCLASS
This section describes how to use the LCLASS statement to define ILM-20 lines for the
X.25 PSCS LAPB implementation.
———————————————————————————————————————
———————————————————————————————————————
LPH=(ILML,'PSCSHDLC')
ILML Specifies an ILM line. This parameter is required for the ILM platform to initialize the
lines associated with this statement.
`PSCSHDLC'
The name of the DCP file that holds pre-registration information. Enclose this name in
quotation marks.
OPTIONS=(DIR,SYFD)
Specifies a direct, synchronous, full-duplex line, which the X.25 protocol requires.
SPEED=speed
The line speed for lines referencing this LCLASS statement. The ILM–20 supports an aggregate
capacity of two million bps.
———————————————————————————————————————
The following example shows an LCLASS specifying the ILM-20 LAPB implementation
and a direct, synchronous, full-duplex line running at 250 kbps.
Note: The ILM-20 supports an aggregate speed of two million bits-per-second
(mbps). If you configure more than one line on an ILM-20 and if the lines
reference a common LCLASS statement, the value on the SPEED parameter
multiplied by the number of lines associated with this ILM-20 cannot exceed
two mbps.
———————————————————————————————————————
7831 5470–200 6–35

LINE
6.6. LINE — Defining Physical Communications
Lines
Format
Parameters
Examples
6–36
The LINE statement defines certain characteristics of communications lines. It has
been modified for X.25 PSCS to define a PDNGRP statement as a parent facility.
———————————————————————————————————————
———————————————————————————————————————
PDNGRP=parnt
Specifies the parent facility (always a PDNGRP) for a PDN connection.
CLASS=lclass
Specifies the associated LCLASS statement which defines the line handler protocol and line
speed.
ADR={port|(port,linenum)}
Specifies the port processor identification number. Values range from 0 to 255. When using
ILM–20 lines, you must also specify the line module's line number. Values range from 0 to 3.
———————————————————————————————————————
Example 1
Example 1 defines an X.21, X.21 bis, or V.35 line. The LINE statement specifies a
PDNGRP statement as the parent facility. The associated LCLASS statement specifies
LPH=X25PKT and OPTIONS=(DIR,SYFD). Both of these LCLASS parameters and
values are required with standard line modules.
7831 5470–200

Example 2
LINE
Example 2 defines a multilink procedure configuration. The LINE statements reference
the same PDNGRP statement, which specifies the multilink option.
Example 3
Example 3 defines an ILM-20 line module. Parameters on the LINE statement are the
same as in Example 1 and Example 2. The associated LCLASS statement, however,
specifies LPH=(ILML,PSCSHDLC). For an ILM-20, you must also specify one of the
four lines on the line module. In this example, the second line (“1”) is specified. The
line numbers range from 0 to 3.
Note: 1. Multiple LINE statements may not have a common PDNGRP parent
unless the PDNGRP statement specifies the multilink procedure. If so, up
to 48 LINE statements can specify the same PDNGRP as a parent.
2. LINE statements that specify resiliency should not use the RESIL
parameter (see the PDNGRP statement), but should specify the ADR and
LSMI parameters when connected to a line switch module (LSM).
———————————————————————————————————————
7831 5470–200 6–37

PDNGRP
6.7. PDNGRP — Defining a Network Connection
6–38
The PDNGRP statement is not a standard Telcon statement but was created especially
for X.25 PSCS. It defines the following:
• Certain packet level attributes for the DCP connection to a network
• The backup processor in resilient configurations
• Parameters for DDN configurations
• Parameters for configurations that use the multilink protocol
• Parameters for DCE Network configurations
You can configure up to 300 PDNGRP statements for each DCP and up to eight of
these can specify the multilink procedure. PDNGRPs reference X25DEF, DTETYPE,
and X25ROUTE statements and are referenced by LINE and DTE statements. Usually,
each LINE statement references a separate PDNGRP statement. In multilink
configurations, however, up to 48 LINE statements can reference the same PDNGRP.
———————————————————————————————————————
7831 5470–200

6.7.1. PDNGRPs for PDNs and Private Packet Networks
Format
Parameters
PDNGRP
This section explains how to use the PDNGRP statement in a PDN or private packet
network environment.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=parnt
Specifies the PRCSR statement that defines the DCP to which this PDNGRP is associated. Up to
300 PDNGRP statements can reference a single PRCSR statement.
X25DEF=netdef
Specifies an X25DEF statement, which associates this PDNGRP with an X25DEF statement.
VCGRP=(fchan,lchan[,type])
fchan Specifies the first logical channel number of a type of virtual circuit. Values may range
from 1 to 4,095. See the network administrator for information on logical channel
ranges.
lchan Specifies the last logical channel number for this type. Values may range from 1 to
4,095. This value must be greater than or equal to fchan. Do not configure more than
1,900 logical channels for each PDNGRP statement.
Note: Special rules apply for specifying these logical channel numbers when the associated
X25DEF statement has specified the L3OPT=3 parameter option (allowing logical
channel zero to be used as a data circuit). See Example 4 below.
7831 5470–200 6–39

PDNGRP
6–40
type Specifies the type of virtual circuit. A description of each type follows:
Default
PERM Specifies permanent virtual circuits (PVCs). If you choose this option, the
values on the PERMVC parameter of the associated DTE statement must fall
within the range of logical channel numbers specified on this statement.
SVC Specifies two-way switched virtual circuits (SVCs).
RIC Specifies switched virtual circuits for outgoing calls only. Incoming calls on
these circuits are cleared.
ROC Specifies switched virtual circuits for incoming calls only.
Two–way switched virtual circuits (SVCs) are the default.
X25ROUTE=route
Specifies the route selected.
DTETYPE=dtype
Specifies a DTETYPE statement. X.25 PSCS uses this DTETYPE reference to determine how to
process calls from nonconfigured DTEs that do not specify certain packet level parameters. If
call packets from a nonconfigured DTE do not specify a flow control negotiation facility, X.25
PSCS uses the information on the associated DTETYPE statement to establish packet level
parameters, such as window and packet sizes. Calls from nonconfigured DTEs that do not
specify a flow control negotiation facility, use the X.25 PSCS defined defaults, which are a
window size of 2 and a packet size of 128.
DTEADR='adr'
Specifies the local DTE address. This parameter is required for the ARPAC, DDN, IBERPAC, and
TELEPACP networks. If you specify this parameter, X.25 PSCS places the local DTE address into
the calling DTE address field of call request packets. If you specify the X.75 option for this
network connection (PDNGRP), the address of the calling, directly attached DTE (DAD) is
substituted for this address. This address is also used to validate the called DTE address in
incoming call packets. Specify up to 15 digits.
RESIL=bdcp
Specifies the name of the backup processor (DCP) to be activated whenever the parent
processor fails. Be sure to specify the ADR and LSMI parameters on the associated LINE
statement.
MLPW=window
Specifies the multilink window size, which specifies the maximum number of sequentially
numbered multilink frames that can be transferred without acknowledgment. See your network
administrator for the correct value.
7831 5470–200

Examples
OPTIONS=(opt1,opt2,...)
Specifies the following options:
MLP Specifies the multilink procedure. The default is no multilink option.
PDNGRP
HIPRI Specifies that this PDNGRP supports calls specifying the priority facility option, which is
defined in the 1988 ITU/TSS Blue Book. When specified, facility parameter values for
the priority of data on a virtual circuit connection are processed in call set up packets.
Valid values range from 0 (least expedited data) to 3 (most expedited data).
X75 Specifies an X.75 interface for a DCE Network. This option is required to enable a DCE
Network to pass a calling DTE address in a call packet to another network. Specify this
option only if you configure the DCE Network feature.
THRUCLAS
Specifies that throughput class negotiation is available on this network connection. The
default is that throughput class negotiation is not available. When specified,
nonconfigured call requests to the network may contain the throughput class
negotiation facility. Note that call requests that are configured use the DTE statement
and its associated DTETYPE statement to determine whether or not the call request
contains the throughput class negotiation facility.
FLOWC Specifies that flow control negotiation is available on this network connection. The
default is that flow control negotiation is not available. When specified, nonconfigured
call requests to the network may contain the flow control negotiation facility. Note that
call requests that are configured use the DTE statement and its associated DTETYPE
statement to determine whether or not the call request contains the flow control
negotiation facility.
———————————————————————————————————————
Example 1
Example 1 defines a connection to a DN1-compatible network. It specifies switched
virtual circuits for logical channels 1 - 9 (VCGRP=(1,9,SVC)) and permanent virtual
circuits on logical channels 10 - 21 (VCGRP=(10,21,PERM)). The associated DTE
statement specifies permanent virtual circuit numbers to match the PDNGRP
specification, although the numbers on the DTE PERMVC parameter do not have to
match, but fall within the range specified on the PDNGRP statement.
7831 5470–200 6–41

PDNGRP
6–42
Example 2
Example 2 defines a multilink procedure configuration. The PDNGRP statement
specifies OPTIONS=MLP and a multilink window size of 21 frames (MLPW=21). The
LINE statements reference the same PDNGRP statement.
Example 3
Example 3 shows the PDNGRP statement in a resilient configuration.
Example 4
Example 4 defines how to configure the logical channel number ranges when the
network allows logical channel zero to be used as a data circuit. This is done by
specifying the L3OPT=3 parameter option on the X25DEF statement associated with
the PDNGRP statement. If the network administrator assigns logical channel numbers
0 through 9 as permanent circuits and numbers 10 through 50 as switched circuits, the
logical channel numbers specified on the VCGRP parameter would be one greater than
that assigned by the network administrator.
———————————————————————————————————————
7831 5470–200

6.7.2. PDNGRPs for the DDN
Format
Parameters
PDNGRP
This section explains how to use the PDNGRP statement in the DDN environment.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=parnt
Specifies the PRCSR statement that defines the DCP to which this PDNGRP is associated. Up to
300 PDNGRP statements can reference a single PRCSR statement.
X25DEF=netdef
Specifies an X25DEF statement, which associates this PDNGRP with an X25DEF statement that
defines the characteristics of the X.25 network interface.
VCGRP=(fchan,lchan[,type])
fchan Specifies the first logical channel number of a type of virtual circuit. Values may range
from 1 to 4,095. See the network administrator for information on logical channel
ranges.
lchan Specifies the last logical channel number for this type. Values may range from 1 to
4,095. This value must be greater than or equal to fchan. Do not configure more than
2,000 logical channels for each PDNGRP statement.
Note: Special rules apply for specifying these logical channel numbers when the associated
X25DEF statement has specified the L3OPT=3 parameter option (allowing logical
channel zero to be used as a data circuit).
7831 5470–200 6–43

PDNGRP
6–44
type Specifies the type of virtual circuit. A description of each type follows:
Default
PERM Specifies permanent virtual circuits (PVCs). If you choose this option, the
values on the PERMVC parameter of the associated DTE statement must fall
within the range of logical channel numbers specified on this statement.
SVC Specifies two-way switched virtual circuits (SVCs).
RIC Specifies switched virtual circuits for outgoing calls only. Incoming calls on
these circuits are cleared.
ROC Specifies switched virtual circuits for incoming calls only.
Two–way switched virtual circuits (SVCs) are the default.
X25ROUTE=route
Specifies the route selected.
DTEADR='adr'
Specifies the local DTE address. The DDN requires this parameter. See the network
administrator for the DTE address.
DTETYPE=dtype
Specifies a DTETYPE statement. X.25 PSCS uses this DTETYPE reference to determine how to
process calls from nonconfigured DTEs that do not specify certain packet level parameters. If
call packets from a nonconfigured DTE do not specify a flow control negotiation facility, X.25
PSCS uses the information on the associated DTETYPE statement to establish packet level
parameters, such as window and packet sizes. Calls from nonconfigured DTEs that do not
specify a flow control negotiation facility, use the X.25 PSCS defined defaults, which are a
window size of 2 and a packet size of 128.
RESIL=bdcp
Specifies the name of the backup processor (DCP) to be activated whenever the parent
processor fails. Be sure to specify the ADR and LSMI parameters on the associated LINE
statement.
7831 5470–200

IMP=(psn)
PDNGRP
Specifies an IMP or packet switching node (PSN) number assigned to the DCE by the DDN. This
parameter is required only when the DCP configures logical hosts. Specify a value from 0 to
255. Use this number with the TCP-IP Stack program product.
IPHOST=(host1...host16)
Specifies logical host numbers assigned to the DTE by the DDN. This parameter is required for
logical host configuration on the DDN. You can specify up to 16 host numbers. Use this number
with the TCP-IP Stack program product.
OPTIONS=(opt1,opt2,...)
Specifies the following options:
THRUCLAS Specifies that throughput class negotiation is available on this network connection.
The default is that throughput class negotiation is not available. When specified,
nonconfigured call requests to the network may contain the throughput class
negotiation facility. Note that call requests that are configured use the DTE
statement and its associated DTETYPE statement to determine whether or not the
call request contains the throughput class negotiation facility.
HIPRI Specifies that this PDNGRP accepts calls specifying priority circuits. When
specified, facility parameter values for the priority of data on a virtual circuit
connection are processed in call set up packets. Valid values range from 0 (least
expedited data) to 3 (most expedited data).
FLOWC Specifies that flow control negotiation is available on this network connection. The
default is that flow control negotiation is not available. When specified,
nonconfigured call requests to the network may contain the flow control
negotiation facility. Note that call requests that are configured use the DTE
statement and its associated DTETYPE statement to determine whether or not the
call request contains the flow control negotiation facility.
———————————————————————————————————————
7831 5470–200 6–45

PDNGRP
Examples
6–46
Example 1
Example 1 defines a connection to the DDN. It specifies switched virtual circuits for
logical channels 1 - 9 (VCGRP=(1,9,PERM)) and permanent virtual circuits on logical
channels 10 - 21 (VCGRP=(10,21,SVC)). The associated DTE statement specifies
permanent virtual circuit numbers to match the PDNGRP specification, although the
numbers on the DTE's PERMVC parameter do not have to match, but simply fall
within the range specified on the PDNGRP statement.
Example 2
Example 2 shows the PDNGRP statement in a resilient configuration.
Example 3
Example 3 shows the PDNGRP statement configuring logical host and PSN numbers.
———————————————————————————————————————
7831 5470–200

6.7.3. PDNGRPs for DCE Networks
Format
Parameters
This section explains how to use the PDNGRP statement in a DCE network
environment.
PDNGRP
———————————————————————————————————————
———————————————————————————————————————
PRCSR=parnt
Specifies the PRCSR statement that defines the DCP to which this PDNGRP is associated. Up to
300 PDNGRP statements can reference a single PRCSR statement.
X25DEF=netdef
Specifies an X25DEF statement, which associates this PDNGRP with an X25DEF statement.
VCGRP=(fchan,lchan[,type])
fchan Specifies the first logical channel number of a type of virtual circuit. Values may range
from 1 to 4,095.
lchan Specifies the last logical channel number for this type. Values may range from 1 to
4,095. This value must be greater than or equal to fchan. Do not configure more than
2,000 logical channels for each PDNGRP statement.
Note: Special rules apply for specifying these logical channel numbers when the associated
X25DEF statement has specified the L3OPT=3 parameter option (allowing logical
channel zero to be used as a data circuit).
type Specifies the type of virtual circuit. A description of each type follows:
Default
SVC Specifies two-way switched virtual circuits (SVCs), which are the default.
RIC Specifies switched virtual circuits for outgoing calls only. Incoming calls on
these circuits are cleared.
ROC Specifies switched virtual circuits for incoming calls only.
Two–way switched virtual circuits (SVCs) are the default.
7831 5470–200 6–47

PDNGRP
Examples
6–48
RESIL=bdcp
Specifies the name of the backup processor (DCP) to be activated whenever the parent
processor fails.
MLPW=window
Specifies the multilink window size, which specifies the maximum number of sequentially
numbered multilink frames that can be transferred without acknowledgment.
OPTIONS=(opt1,opt2,...)
Specifies the following options:
DAD Specifies a directly attached DTE. Call packets from the DTE defined here are routed
based on the called DTE address only. You must specify OPTIONS=DAD for DCE
Network PDNGRPs.
MLP Specifies that this network connection supports the multilink procedure. The default is
no multilink option.
HIPRI Specifies that this PDNGRP supports calls specifying the priority facility option as
defined in the 1988 ITU/TSS Blue Book. When specified, facility parameter values for
the priority of data on a virtual circuit connection are processed in call set up packets.
Valid values range from 0 (least expedited data) to 3 (most expedited data).
———————————————————————————————————————
Example 1
Example 1 shows a DTE connected to the DCE network. The PDNGRP statement
specifies OPTIONS=DAD.
Example 2
Example 2 is similar to Example 1 except it also specifies high priority virtual circuits.
The PDNGRP statement specifies OPTIONS=(DAD,HIPRI).
———————————————————————————————————————
7831 5470–200

Online configuration differences
PDNGRP
1. Most online configuration changes take effect when you issue the DOWN and UP commands
for the LINE whose parent is this PDNGRP. When you change the VCGRP parameter, however,
you must restart Telcon before configuration changes take effect.
2. In order to remove the local DTE address, enter DTEADR=NONE, then issue the DOWN and
UP commands for the associated LINE statement.
3. In order to remove the X25ROUTE, enter X25ROUTE=NONE, then issue the DOWN and UP
commands for the associated LINE statement.
———————————————————————————————————————
7831 5470–200 6–49

PDNPAD
6.8. PDNPAD — Defining Operational Parameters
for a PAD
Format
Parameters
6–50
The PDNPAD statement is not a Telcon statement but was created especially for X.25
PSCS to define operating characteristics for terminals using the X.29 PAD feature.
These operating characteristics are used by a network X.29 PAD to set up a terminal
operating environment. Recommendation X.3 defines operating characteristics which
may be specified on this statement, and are detailed below. For network or private
X.29 PAD interfaces that allow non-standard terminal operating characteristics, you
may also specify these locally-defined operating parameters and values.
TERM statements reference PDNPAD statements. After a terminal user has signed on,
X.25 PSCS automatically sends the X.3 operating characteristics specified on the
PDNPAD statement to the network X.29 PAD, setting up the operating environment
required for that terminal.
———————————————————————————————————————
———————————————————————————————————————
PRCSR=prcsr
Specifies the PRCSR statement that defines the DCP to which the terminal is connected.
X3P01=value
Defines a PAD recall character. Specify one of the following values:
0 Does not allow return to PDN control state.
1 Generates an ASCII DLE (hexadecimal 10) character.
32-126 Are user-defined characters that define a graphic character that you may enter at the
terminal to escape from the data transfer state and recall the PAD control state. The
value of the character is the binary representation of the decimal value in accordance
with ITU/TSS Recommendation, International Alphabet No. 5, Volume 8 FASCICLE XIII.1
V.3.
For example, to specify capital letter H as the escape character, specify:
Decimal 72 equals hexadecimal 48, which equals ASCII capital letter H.
7831 5470–200

X3P02=value
Defines echo function.
0 Specifies no echo
1 Specifies echo
If parameter 20 is implemented, it determines which characters are echoed.
X3P03=value
PDNPAD
Selects the data forwarding signal. Use a decimal value to specify the required functions. The
following values may be added to combine any required character codes:
0 Indicates no data forwarding character
1 Alphanumeric characters (A-Z, a-z, 0-9)
2 Character CR
4 Characters ESC, BEL, ENQ, ACK
8 Characters DEL, CAN, DC2
16 Characters ETX, EOT
32 Characters HT, LF, VT, FF
64 All other nonprintable characters; hexadecimal 01 to 1F
For example, to designate characters ETX, EOT, and CR, specify:
X3P04=value
Selects the idle timer delay. Any decimal value from 0 to 255 may be specified.
0 Requires no data forwarding on timeout
1-255
Delays in 20ths of a second
X3P05=value
Defines ancillary device control.
0 X-ON (DC-1) and X-OFF (DC-3) are not used.
1 X-ON (DC-1) and X-OFF (DC-3) are used.
7831 5470–200 6–51

PDNPAD
6–52
X3P06=value
Defines control of PAD service signals. Specify the functions required with decimal values.
0 Indicates no service signals are to be transmitted to the start-stop mode DTE
1 Transmits service signals other than the prompt PAD service signal
4 Transmits prompt PAD service signal in standard format
8-15 Transmits PAD service signals in a network-dependent format
X3P07=value
Defines the operation of the PAD on receipt of break signal from the start-stop mode DTE.
Specify a decimal value.
0 Does nothing
1 Sends interrupt packet to X.25 PSCS
2 Resets
4 Sends X.29 indication-of-break PAD message to X.25 PSCS
8 Escapes from data transfer state
16 Discards output to start-stop mode DTE
X3P08=value
Defines the discard output function.
0 Delivers data normally to the start-stop mode DTE
1 Discards output
X3P09=value
Defines the padding after carriage return function.
0-255 Specifies the number of padding characters after each carriage return
Selecting 0 causes no padding characters to be sent, although PAD service signals will contain
some padding characters, according to the data rate of the start-stop mode DTE.
7831 5470–200

X3P10=value
Defines the line folding function. Specify a decimal value as follows:
0 Indicates no line folding required
PDNPAD
1-255 Specifies the number of graphic characters per line, after which the PAD automatically
inserts appropriate format characters
X3P11=value
Do not specify this parameter. It is reserved for the X.25 PSCS software.
X3P12=value
Defines flow control of the PAD by the start-stop mode DTE.
0 Indicates X-ON (DC1) and X-OFF (DC3) are not used
1 Indicates X-ON (DC1) and X-OFF (DC3) are used
X3P13=value
Defines the line-feed insertion after carriage return function.
0 Indicates no line-feed character insertion required
1 Inserts a line-feed character after each carriage return character to the start-stop DTE
2 Inserts a line-feed character after each carriage return character from the start-stop DTE
4 Inserts a line-feed character after each carriage return character in the echo to the
start-stop DTE
X3P14=value
Defines the line-feed padding function.
0-255 Specifies the number of padding characters generated by the PAD after a line-feed
character is transmitted to the start-stop DTE during the data transfer state.
X3P15=value
Defines the editing function.
0 Specifies editing is not used in the data transfer stream
1 Specifies editing is used in the data transfer state. In addition, the following PAD functions
are suspended:
– Data forwarding on a full packet until the editing buffer is full
– Data forwarding on idle timer period expiration (the value specified on the X3P04
parameter is unchanged)
7831 5470–200 6–53

PDNPAD
6–54
X3P16=value
Defines the character delete function.
0-127 Defines a character that may be entered at the terminal to delete a character. The
value of the character is the binary representation of the decimal value in accordance
with ITU/TSS Recommendation, International Alphabet No. 5, Volume 8 FASCICLE XIII.1
V.3.
For example, to define the delete key as a character-delete character, specify:
Decimal 127 equals hexadecimal 7F, which equals the ASCII delete function.
X3P17=value
Defines the line delete function.
0-127 Defines a character that may be entered at the terminal to delete a line. The value of
the character is the binary representation of the decimal value in accordance with
ITU/TSS Recommendation, International Alphabet No. 5, Volume 8 FASCICLE XIII.1 V.3.
For example, to define the cancel function as a line-delete character, specify:
Decimal 24 equals hexadecimal 18, which equals the ASCII cancel function (Control-X).
X3P18=value
Defines the line display function.
0-127 Defines a graphic character that may be entered at the terminal to display a line. The
value of the character is the binary representation of the decimal value in accordance
with ITU/TSS Recommendation, International Alphabet No. 5, Volume 8 FASCICLE XIII.1
V.3.
For example, to specify device control 2 (DC-2) as a line display function, specify:
Decimal 18 equals hexadecimal 12, which equals the ASCII DC-2 function (Control-R).
7831 5470–200

X3P19=value
X3P20
X3P21
Defines the format of the editing-type service signal.
0 Indicates no editing-type PAD service signals are returned to the terminal
PDNPAD
1 Indicates editing-type PAD service signals for printing terminals are returned to the
terminal
2 Indicates editing-type PAD service signals for display terminals are returned to the
terminal
8 Indicates editing-type PAD service signals through use of backspace character are
returned to the terminal
32-126 Defines an ASCII character as the editing character returned to the terminal
Defines which characters will not be echoed.
0 All characters echoed
1 No echoing of carriage returns
2 No echoing of line feeds
4 No echoing of characters VT, HT, FF
8 No echoing of characters BEL, BS
16 No echoing of characters ESC, ENQ
32 No echoing of characters ACK, NAK, STX, SOH, EOT, ETB, ETX
64 No echoing of characters designated by parameters 16, 17, 18
128 Indicates all other non-printable characters (hexadecimal 01 - 1F)
Defines parity checking procedures.
0 No parity checking or generation
1 Parity checking
2 Parity generation
7831 5470–200 6–55

PDNPAD
Examples
6–56
X3P22
Defines page wait procedure.
0 Page wait disabled
1–255 Specifies the number of linefeed characters the PAD sends the terminal before invoking
page wait
LPS=(x,y)
Defines local parameter separator. These two bytes build a 16-bit marker that separates the X.3
standard parameters from the local parameters.
x 0-255, which specifies the value of the first byte of the local parameter separator
y 0-255, which specifies the value of the second byte of the local parameter separator
Default
The default values are zero. Recommendation X.29 defines zero values as the local
parameter separation marker.
LPAR=(pnum,value),...(pnum,value)
Specifies a local parameter number and value. Any number of these values may be used.
This parameter defines local parameters established by the local network administration.
pnum 0-255, which specifies a local parameter.
value 0-255, which specifies a local option.
———————————————————————————————————————
Example 1
Example 1 defines terminal operating characteristics for “break signal” handling. All
other operating characteristics default to whatever the network X.29 PAD interface
has defined. When TERM01 invokes a “break signal,” the X.29 PAD sends an interrupt
packet value to the X.25 PSCS and X.25 PSCS discards any output messages waiting to
be sent to the terminal. These characteristics correspond to values of 1 and 16,
respectively, for X.3 parameter 7. To achieve both these characteristics, the values are
added together when specified on the PDNPAD X3P07 statement parameter.
7831 5470–200

Example 2
PDNPAD
Example 2 defines local operating characteristics implemented by a network X.29
PAD. Here, the network PAD supports parameter 4, the automatic data forwarding
timer, plus local parameter 15. The network X.29 PAD requires a non-zero local
parameter separation marker consisting of two octet values. This marker is used to
distinguish the local parameter 15 definition from the X.3 parameter 15.
———————————————————————————————————————
7831 5470–200 6–57

TERM
6.9. TERM — Defining a Terminal
The TERM statement is a standard Telcon statement that defines terminals. It has
been modified for X.25 PSCS to configure the following:
• Terminals attached to a UTS 4000 Cluster Controller functioning as a configured
DTE
• Terminals using the X.29 PAD capability
Note: This section does not describe configuration for a terminal using the
X.28/PAD because this X.28/PAD configuration does not require changes to
the TERM statement.
———————————————————————————————————————
6.9.1. Terminals Using the UTS 4000 Cluster Controller
Format
Parameters
6–58
This section explains how to use the TERM statement to configure terminals attached
to a UTS 4000 Cluster Controller. The ADR parameter is the only parameter modified
for X.25 PSCS.
———————————————————————————————————————
———————————————————————————————————————
ADR=(cid,pid)
cid Not used by X.25 PSCS. Enter any one-digit number except zero to satisfy the configuration
processor.
pid Specifies a port index within a cluster. X.25 PSCS requires that the first TERM statement
defining a terminal attached to a UTS Cluster Controller be assigned a PID of 1, the second
a 2, the third a 3, and so on. The port index of a remote print interface must follow the last
port index assigned to a workstation.
CCS=ccs
Coded character set parameter.
———————————————————————————————————————
7831 5470–200

Example
The following example defines three terminals attached to a UTS 4000 Cluster
Controller.
TERM
———————————————————————————————————————
6.9.2. Terminals Using the X.29 PAD
Format
This subsection explains how to configure a terminal to use the X.29 PAD feature. A
reference to a PDNPAD statement is the only X.25 PSCS change to this statement.
A terminal user must send the TERM or parent PDNPAD statement name to X.25
PSCS in order to sign on. This is done in one of two ways:
• When a call packet is sent to X.25 PSCS, it searches for a configured TERM or
PDNPAD statement name in the packet's user data field. If a name is found, X.25
PSCS automatically signs onto the terminal. Note that this functionality depends
on the network's X.29 PAD's capabilities.
• After the network X.29 PAD interface has established a packet layer connection,
the terminal user enters the standard Telcon sign on command, $$SON.
Note that if a PDNPAD statement name is used during the sign on procedure, X.25
PSCS automatically selects an available TERM statement name to use for the Telcon
transport connection.
———————————————————————————————————————
———————————————————————————————————————
7831 5470–200 6–59

TERM
Parameters
Example
6–60
PDNPAD=parnt
Specifies the name of a parent PDNPAD statement.
TYPE=type
Specifies one of the following terminal types:
• TTY for teletype models 33 and 35
• DCT500 for terminals using 132 characters per line
• UTS10B for asynchronous buffered mode terminals using ETX
• UTS10C for asynchronous terminals
CCS=ccs
Specifies a coded character set (CCS) value. If a CCS value is specified, the X.29 PAD interface
does not clear the most significant bit of each character. This allows for sending and receiving
binary data.
Default
The default is 7-bit ASCII character, the same as configuring the CCS parameter as
CCS=UNKNOWN. The X.29 PAD interface regards the most significant bit of each character
as a parity bit and clears it.
———————————————————————————————————————
The following example defines a PDNPAD functioning as a parent to a remote
terminal.
Note: Terminals configured for PDN use may not be configured for autoallocation.
———————————————————————————————————————
7831 5470–200

6.10. X25DEF — Defining Network
Characteristics
X25DEF
The X25DEF statement is not a standard Telcon statement but was created especially
for X.25 PSCS. It enables you to define the following:
• A network name that appears on the console screen when an NMS STAT LINE
command is issued
• The size of the information field contained in frames passed between the DCP and
a network or directly attached DTE
• The number of frames that can be sent and received without acknowledgment
• The amount of time to wait before retransmitting an unacknowledged frame
• The number of times to retransmit an unacknowledged frame
• The length of time a channel can remain idle
• The length of time to delay before acknowledging a frame
• An extended frame-level window (modulo 128), which enables up to 128
unacknowledged frames
• Various level 2 and level 3 options to tailor the DCP's connection to a specific
network
Most configurations require only one X25DEF statement. You may need more,
however, if you define connections to more than one network or you want PDNGRPs
associated with the same network to define different network characteristics.
When you use more than one X25DEF statement, X.25 PSCS defines more than one
network only when the NETID or the GLOBALID differ between X25DEF statements.
Specifying the same GLOBALID maintains a single network definition even though
different NETIDs appear on the NETWORK parameter.
In a multiple network-connection environment, the networks perceived by X.25 PSCS
as accessible become crucial when determining over which network connections a call
request packet can be sent. Inconsistent use of the NETID or GLOBALID parameter
values across more than one X25DEF statement can cause call packets to be cleared,
or can cause the call packet to be sent on the wrong network.
———————————————————————————————————————
7831 5470–200 6–61

X25DEF
Format
Parameters
6–62
———————————————————————————————————————
NETWORK=netid
Specifies a network mnemonic, which identifies a set of operating parameters appropriate for
connection to a particular supported network. Table 6–3 provides mnemonics for supported
networks. Table 6–4 lists the values for the N1, N2, T1, T2, T3, L2WINDOW, L2OPT, and L3OPT
parameters associated with a particular mnemonic. If you do not specify this parameter, be sure
the network characteristics defined on this statement's other parameters are appropriate for the
network.
Note: Consult your network administrator to verify that the default values in Table 6–4 (or the
parameter values you specify) match the operating characteristics set by the network
for each physical connection. Often, these characteristics vary for each network
connection, requiring more than one X25DEF statement. Some networks, such as SITA,
define the T1, T2, and T3 timer parameter values based on the line speed.
Individual values specified for N1, N2, T1, T2, T3, L2WINDOW, L2OPT, and L3OPT override the
values associated with a NETID.
———————————————————————————————————————
7831 5470–200

Table 6–3. Network Names and Mnemonics for the X25DEF Statement
Accunet (USA)
Arpac (Argentina)
Austpac (Australia)
Network Name Mnemonic (NETWORK=netid)
BX.25 (USA, private operator)
Datapac (Canada)
Datex (Sweden)
Datex–P 1980 (Austria and Germany)
DCS (Belgium)
DDX (NTT Japan)
Defense Data Network (USA)
DN1 (Netherlands)
Euronet (NET2 certified)
Iberpac (Spain)
Itapac (Italy)
Mexpac (Mexico)
NOPN (Norway)
NPDN (Finland)
PSCSNET (DCE Network feature)
PSS (United Kingdom)
Renpac
SITA (France)
Telenet (USA)
Telepac (Switzerland)
Telepacp (Portugal)
Transpac (France)
ACCUNET
ARPAC
AUSTPAC
BX25
DATAPAC
DATEX
DATEXPA
DCS
DDXP
DDNX25
DN1
EURONET
IBERPAC
ITAPAC
MEXPAC
NOPN
NPDN
PSCSNET
PSS
RENPAC
SITA
TELENET
TELEPAC
TELEPACP
TRANSPAC
X25DEF
7831 5470–200 6–63

X25DEF
Table 6–4. NETID Values
Network N1 N2 T1 T2 T3 L2W L2OPT L3OPT
Accunet
Arpac
Austpac
BX.25
Datapac
Datex
Datex–P (80)
DCS
DDN
DDXP
DN1
Euronet
Iberpac
512
128
1024
1024
512
1024
512
128
1024
128
1024
512
128
2
3
10
20
10
10
10
10
10
7
10
10
3
2000
1500
3000
10K
3000
3000
3000
3000
4000
2000
3000
3000
1500
200
Def
Def
2000
Def
Def
Def
Def
Def
Def
Def
Def
Def
26K
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
7
7
7
7
7
7
7
7
7
7
7
7
7
2,3,6,7,9,10,17
2,3,6,8
2,3,6
2,3,6,7,9,10,16,17
2,3,5,6,7,8
1,2,3
2,3,6,8,9,10,12,13,14
2,3,5,6,7,9
2,3,7,8,9,18
3,6,9,10,12,17
2,3,6,9
2,3,6,8,9,10,12,13,14
2,3,6,8
5,8
2
None
5
8,9
8
None
6
None
2,5,31
2
5,31
2
Itapac
Mexpac
NOPN
NPDN
PSCSNET
PSS
Renpac
SITA
Telenet
Telepac
Telepacp
Transpac
256
1024
1024
1024
1024
1024
1024
256
1024
128
512
1024
10
20
20
10
10
20
3
10
20
10
10
3
3000
3000
3000
3000
3000
3000
1000
3000
3000
3000
3000
1000
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
Def
7
7
7
7
7
7
7
7
7
7
7
7
2,3,5,6,7,8
1
1,3
2,3,5,6,7,8
2,3,5–10,12–14
1,3
2,3,5,6,7,8
2,6,8,12,16,17
4,6,8
2,3,5,6,7,8
2,3,5,6,8
2,3,5,6,7,8
6
None
None
4
None
None
4
None
None
None
None
None
7831 5470–200
6–64

Parameters
NAME='net-name'
X25DEF
Specifies the network identifier (up to eight characters) for Telcon Network Management Services
(NMS) to display when a STAT LINE command is issued for a line associated with this network.
Default
IDENT=globalid
The default is the netid specified on the NETWORK parameter.
Specifies a global network identifier, which identifies a network and differentiates between
networks when more than one X25DEF statement is configured. If an upper layer program is
unable to identify a PDN by the X25DEF STE index or network identifier (netid), it can use the
global network identifier. Values for this parameter range from 0 through 255.
N1=frame–size
Specifies the maximum length of the information field in frames passed between the DCP and a
network. Specify sizes of 16, 32, 64, 128, 256, 512, 1,024, 2,048, or 4,096 octets.
Default
N2=rxmit–count
There are two defaults. If you used the NETWORK parameter, the network's default is used.
Otherwise, the default is 128. Make sure the size does not exceed network maximums.
Specifies the maximum number of frame retransmissions following the expiration of the T1 timer.
The range is 0 – 255.
Default
There are two defaults. If you specified a netid on the NETWORK parameter, the network's
default is used. Otherwise, the default is 10.
X25ROUTE=route
Specifies the route selected.
7831 5470–200 6–65

X25DEF
6–66
T1=t1–timer
Specifies the period of the T1 timer. When this timer expires, a frame may be retransmitted. The
range is from 1 – 60,000 milliseconds.
The value of the T1 timer must be greater than the maximum time between when frames are
transmitted (for example, SABM, DM, DISC, FRMR, I, or an S-format command with its P-bit set to
1) and the corresponding frame is returned as an answer to this frame (for example, UA, DM, or
acknowledging frame).
Default
T2=t2–timer
There are two defaults. If you specified a NETID on the NETWORK parameter, the network's
default is used. Otherwise, the default is computed as the time taken to transmit a frame
(based on line speed multiplied by 3.5).
Specifies the response delay timing, which defines the maximum time the DTE delays before
acknowledging SABM, DM, DISC, FRMR, I frames, or an S-format command with its P-bit set to 1.
T2 must be less than the value specified by the T1 parameter. The range is 1 – 60,000
milliseconds, and the default is to respond at the earliest opportunity. X.25 PSCS does not use
this parameter for ILM-20 lines.
T3=t3–timer
Specifies the length of time a channel can remain idle. This parameter conforms to ITU/TSS
(CCITT) 1984 X.25 Recommendation, which calls the parameter the "excessively long idle
channel state." Set this timer to expire between 1 – 60,000 milliseconds, but set it for a period
greater than that specified for the T1 timer. X.25 PSCS does not use this parameter for ILM-20
lines.
L2WINDOW=k
Specifies the frame-level window size, which defines the maximum number of frames that can be
sent and received without acknowledgment. For standard X.25 line modules, the range is
between 1 and 7. For ILM-20 lines, the range is between 1 and 127. If you specify a window size
greater than 7, you must also specify EXTENDED=YES.
Default
EXTENDED=YES
For standard X.25 lines, the default is 7.
Specifies modulo 128, which enables up to 127 unacknowledged frames, instead of the normal
seven frame maximum. Use this with ILM-20 lines only.
7831 5470–200

DTETYPE=dtype
X25DEF
Specifies a DTETYPE statement, which defines the DTE-to-DCE interface packet layer flow control
parameters for all network connections (PDNGRPs) associated with this statement. Both the DTE
and PDNGRP statements (when referencing a DTETYPE statement) override the parameters
specified from this reference.
DTX=YES
Specifies a point-to-point connection to another DTE in which the DCP acts as the DCE. Use this
parameter with the DCE Network feature and to configure a non-DCE Network point-to-point
connection.
Default
The default is NO.
L2OPT=option1,...,option31
Level 2 options determine the operation of the link level protocol. Specify as many as required
(X.25 PSCS does not use this parameter for ILM-20 lines). They are explained as follows:
1 Specifies that the DTE and DCE go through a disconnected phase prior to establishing
a mode. If this option is not specified, the mode is established immediately.
2 Specifies that the network allows a DM command from the DTE. Do not specify this
value if the network does not recognize a DM command.
3 Specifies that the network transmits the DM command. Do not specify this value if the
network does not transmit the command and any DM command received is ignored.
4 Specifies that the DTE transmits a disconnect command prior to attempting to
reestablish a link with a SABM after the DTE has detected a fault or timeout (T1 X N2).
Do not specify this value if you want the DTE to continue attempting to establish the link
with SABM transmissions after detecting a fault or a timeout (T1 X N2).
5 Specifies that the DTE transmits a DM when the network responds to a SABM with a
frame-reject. Do not specify this value if the DTE sends SABM when the network
responds with a frame-reject.
6 Specifies that the DTE supports the SABM collision state. The DTE considers the link to
be initialized upon issuing a UA and does not require its SABM to be acknowledged with
a UA from the DCE. Do not specify this value if the DTE does not support a SABM
collision state. In this case, the DTE responds to a SABM with a UA, even when it has
just sent a SABM and expects the DCE to respond to the outstanding SABM with a UA.
7 Specifies that the DTE responds to a DISC command with a DM and then the DTE is in
either the silent or sending DM state. Do not specify this value if the DTE responds to a
DISC command with a UA when the DTE is in the sending DM state and does not have a
silent state. The DTE should attempt to reestablish the link after it is disconnected.
7831 5470–200 6–67

X25DEF
6–68
8 Specifies that the DCE sends an FRMR when it receives an unsolicited UA in the
information transfer state. Do not specify this value if the DTE ignores an unsolicited UA
in the information transfer state.
9 Specifies that the DTE resets the link when it receives an unsolicited F-bit in a response
frame. Do not specify this value if the DTE sends an FRMR when it receives an
unsolicited F-bit in a response frame.
10 Specifies that the DTE resets the link when it receives an unsolicited UA in the
information transfer state. This option overrides option 8. If you do not specify this
value, option 8 dictates the recovery procedure.
11 Specifies when parameter DTX=YES and the other DTE initiates link establishment.
12 Specifies that when layer 2 is in the frame-reject state, the T1 timer value is ignored.
That is, FRMR frames are not retransmitted. Do not specify this value if you want the T1
timer value to be honored while in the frame-reject state.
13 Specifies that the F-bit should be set in an FRMR when the invalid input frame had the
P/F-bit set. Do not specify this value if the P/F-bit setting is irrelevant in an invalid input
frame. The FRMR will have the F-bit clear.
14 Specifies that during link establishment the DTE responds to supervisory or information
frames that have the P-bit set with a DM and responds to a DM frame with a SABM with
the P–bit set. Do not specify this value if the supervisory, information, or DM frame
should be ignored during link establishment.
15 Reserved.
16 Specifies that the link level inform level 3 of a link reset when it receives an SABM while
in the information transfer state.
Do not specify if the link level should not inform level 3 of a link reset when it receives
an SABM while in the information transfer state.
17 Specifies that the DTE sends a polled receive ready frame after a period of T1 times
N2 has elapsed in the information transfer state and no frames have been sent or
received during that period.
Do not specify this value if no receive ready frame should be sent in these
circumstances.
18 Specifies than an unsolicited UA received in the frame reject state is ignored.
Do not specify this value if an unsolicited UA received in the frame reject state is
processed.
19–31 Reserved.
7831 5470–200

L3OPT=(option1,...,option31)
Level 3 options determine the operation of the packet level protocol. Specify as many as
required. They are explained as follows:
X25DEF
1 Specifies that the network provides end-to-end acknowledgment at level 3 and that you
prefer this to the LEVEL4 transport protocol's end-to-end acknowledgment.
Do not specify this value if the network does not provide end-to-end acknowledgment or
it is provided by LEVEL4.
2 Specifies that the DTE responds with a CLEAR/RESET when it receives a packet with an
invalid general format identifier (GFI).
Do not specify this value if the DTE ignores a packet with an invalid GFI.
3 Specifies that the DCE does not follow the ITU/TSS Recommendation and transmits
packets other than restart on logical channel zero.
Do not specify this value if the DCE transmits only restart packets on logical channel
zero.
4 Specifies that the network rounds up the called DTE address field in an incoming call to
an integral number of octets, when necessary, by appending four 0 bits to the field.
The called/calling address combination is assumed to be rounded up in all cases.
Do not specify this value if the network does not pad out the called DTE address when
it has an odd number of digits.
5 Specifies that the DTE address length and facility length fields must be present in CALL
CONNECTED, CALL ACCEPTED, CLEAR REQUEST, CLEAR CONFIRMATION, or CLEAR
INDICATION packets, even though the length values are zero.
Do not specify this value if the DTE address length and facility length fields need not be
present when the length values are zero.
6 Specifies that the network uses the throughput class facility to imply window size
negotiation. Do not specify this value if window size negotiation is not assumed from
the throughput class facility.
7 Reserved.
8 Specifies a prefix digit on the called DTE address for international connections. (An
international connection is one in which the called DTE is not on the network defined by
this X25DEF statement.) Do not specify this value if the network does not require a
prefix digit for an international connection.
9 Specifies that the prefix digit on the called DTE address is 1. Specify option 8 if you
specify option 9.
7831 5470–200 6–69

X25DEF
6–70
10 Specifies that the calling DTE address in a call packet from a directly attached DTE
(DAD) on a DAD–configured line (OPTIONS=DAD on PDNGRP statement) is validated
against the address configured on the DTE statement. If the addresses do not match,
the call is cleared.
11 Specifies that the received calling address is validated against the configured address.
If the call does not have a calling address, it is cleared.
12–30 Reserved.
31 Specifies that the PDN supports the 1984 amendments to Recommendation X.25. This
option allows the following:
– Facility fields longer than 63 octets
– Transit delay feature
– Nonzero or DTE created cause codes sent to the network
– Frame and packet sizes greater than 1,024 octets
– Up to 128 octets of user data in clear packets for a connection using the fast
select option
———————————————————————————————————————
7831 5470–200

Examples
Example 1
Example 1 defines the network characteristics of the Telenet PDN. No other
parameters are required.
Example 2
X25DEF
Example 2 defines a network with a global network identifier value of 24. The DCP
end user program interfaces to PSCS maintains the value for identifying a network
when initiating a connection. Also, the host application program passes the value
when identifying the network.
Example 3
Example 3 defines two networks, even though the netids on the NETWORK
parameters are the same and all PDN lines may be connected to the same network.
This definition allows “class of service” choices to the same network.
Example 4
Example 4 defines one network even though the netids are different and the PDN lines
are connected to different networks (the netid for X25DFPR1 is zero). If connectivity
to a remote DTE is achieved through either physical connection, only a single network
definition is necessary.
———————————————————————————————————————
7831 5470–200 6–71

X25DEF
Online configuration differences
6–72
1. To make changes to the X25DEF statement, the LINE associated with this statement (via the
PDNGRP statement) must be placed in a DOWN condition and then an UP condition.
2. To clear all L2OPT or L3OPT options to zero, enter L2OPT=0, L2OPT=NONE or L3OPT=0,
L3OPT=NONE. Then enter the option values you want.
3. Entering L2OPT or L3OPT values replaces previously entered values.
4. To remove any currently specified X25ROUTE, enter X25ROUTE=NONE.
———————————————————————————————————————
7831 5470–200

6.11. X25NET — Defining DCE Network Routes
Format
Parameters
X25NET
The X25NET statement is used exclusively in DCE network configurations, providing
the Telcon network with call routing information. It references PRCSR and XEU
statements.
X25NET statements are associated with individual DCP/DCEs through the PRCSR
parameter. Each DCE requires an X25NET statement for every other DCE to which it
routes calls. For example, networks consisting of a single DCE do not require X25NET
statements, but those with two DCEs require two X25NET statements, each providing
routing information on the other. Additional X25NET statements are required when
another DCE provides a gateway to an external X.25 network.
———————————————————————————————————————
name X25NET PRCSR prcsr, XEU xeu,
,DESTID 'dce num'
,DNICID 'dnic'
———————————————————————————————————————
PRCSR=prcsr
Specifies the PRCSR statement that defines the DCP to which this X25NET statement is
associated.
XEU=xeu
Specifies an XEU statement, which associates a node number (DESTID) or DNIC (DNICID) with a
Telcon transport route.
DESTID='dce-num'
Specifies the node number of a destination DCE. This address is a subset of the complete DTE
address that appears on a DTE statement and a subset of the address specified on the
DCENODE parameter of the EU statement. Specify either DESTID or DNICID, but not both.
Enclose this number in quotation marks.
DNICID='dnic'
Specifies a DNIC. Call request packets carrying this DNIC are routed to the DCE connected to a
network identified by the DNIC. Specify either DESTID or DNICID, but not both. Enclose this
number in quotation marks.
———————————————————————————————————————
7831 5470–200 6–73

X25NET
Examples
6–74
Example 1
Example 1 shows how to use the X25NET statement in a two-node DCE network
configuration. There are two X25NET statements. Each specifies the following:
• The DCP with which it is associated
• The DCE node number of the other node (DESTID parameter)
• The name of the XEU associated with the other DCP
Example 2
Example 2 shows how to use the X25NET statement in a two-node network with an
X.75 interface to another network. There are three X25NET statements. The first two
statements provide the node number and associated XEU statement of the other DCP.
The third X25NET statement specifies a DNIC, indicating that the DCP associated with
the XEU named DCE1 is a gateway to another packet network.
———————————————————————————————————————
7831 5470–200

6.12. X25ROUTE — Specifying Routing
Precedence
Format
Parameters
X25ROUTE
The X25ROUTE statement specifies the precedence and routing used by a given line
or network. Precedence indicates the order of the four routing methods X.25 PSCS can
use. Routing indicates to which level 4 X.25 PSCS routes the incoming call. If the
X25ROUTE statement is not present, the routing precedence is by calling address,
protocol ID, and default level 4. This is the same routing precedence followed in
previous releases. The DCE Network feature does not use X25ROUTE configuration
statements.
———————————————————————————————————————
———————————————————————————————————————
SEARCH=(par1[,par2][,par3][,par4])
Specifies the search precedence and search type. A search type of ADDRESS, PROTOCOL,
SUBADR, and LEVEL4 cannot be used more than once per X25ROUTE. Any of these search
methods, in any order, may be specified. The search precedence decreases from left to right.
If the X25ROUTE statement is not configured, incoming calls are routed by calling DTE address,
protocol ID, and default level 4.
, , ,
= , , , depending on par1
= , , , depending on par1 and par2
= , , , depending on par1, par2, and par3
ADDRESS= Searches the calling address for a match in the configured DTE statements. The
LEVEL4 associated with a matched DTE statement is used for routing.
LEVEL4= Indicates that the layer 4 program to route the incoming call is specified on the
LEVEL4 parameter.
7831 5470–200 6–75

X25ROUTE
6–76
PROTOCOL=
Searches the user data for a protocol ID match. If a match is made, the LEVEL4
associated with the protocol may be used for routing. The list of acceptable level 4
programs is identified on the PROTOCOL parameter.
SUBADR= Searches the last digits of the called address for a match. If a match is made, the
LEVEL4 as specified in the subaddress list specified on the SUBADR parameter is
used.
LEVEL4=(lvl4)
Specifies that a default level 4 was used in the SEARCH field.
lvl4 Specifies the default level 4 where incoming calls are routed. The level 4 list is the
same as on the SUBADR parameter.
SUBADR=(lvl4,'nn')
Lists level 4 types with associated subaddresses.
lvl4 Identifies the level 4 type for this subaddress match. These level 4 types are selected
from the list of level 4 types specified on the DTETYPE configuration statement. The
level 4 types IPOSI, TPOSI, TPCCITT, IPTCP, X29PAD, PDNNPID, PDNIPID, PDNUPID,
and VIDEOTEX can all use subaddress routing. All other level 4 types can not.
nn Indicates 1 or 2 decimal digits for the subaddress, with n1>0 and n1

Example
PROTOCOL=(lvl4[,lvl4]...)(ALLPROT)
X25ROUTE
Identifies a list of the level 4 types where incoming calls may be routed based on the protocol
identifier contained within the incoming call.
lvl4 Specifies the level 4 types where incoming calls may be routed. These are selected
from the level 4 types IPOSI, TPOSI, TPCCITT, IPTCP, X29PAD, PDNNPID, PDNIPID,
PDNUPID, or VIDEOTEX.
X29PAD and VIDEOTEX are mutually exclusive. The X.29 identifier is the same for both.
Incoming calls with the X.29 identifier are routed to X29PAD, VIDEOTEX, or neither,
depending on the protocol list.
ALLPROT
Specifies all level 4 types on the PROTOCOL parameter. When using the ALLPROT
option, any protocol identifier in an incoming call will be used for routing to a level 4
type.
Note: For the X.29 protocol identifier, the X29PAD level 4 will receive the incoming
call.
———————————————————————————————————————
The following example defines a search precedence. Incoming call packets are initially
routed to a layer 4 program based upon matching the subaddress digits in the called
DTE address with those configured on the SUBADR parameter. If no match occurs,
routing is based upon the calling DTE address matching any configured addresses on
DTE statements. If no match occurs, the call is routed to the X.29 PAD terminal
handler because it was specified as the default layer 4 on the LEVEL4 parameter.
Note: The DTEADR='311080100040' on the PDNGRP statement PGP1 is not
required, and is only included to indicate that the last two digits (40) are
not found, and must not be used, in the subaddress routing list specified in
the X25ROUTE statement.
———————————————————————————————————————
7831 5470–200 6–77

X25ROUTE
Online configuration differences
6–78
1. Wherever a search type or level 4 type can be specified, NONE can be specified to clear a
prior specification.
2. A pre–existing SUBADR parameter can be "skipped" by specifying SUBADR=(,) for each
SUBADR parameter to be skipped. The number of SUBADR parameters specified is
used to determine how many SUBADR entries are put in the resulting table. It may be
necessary to skip any parameters beyond those being changed. If in doubt, specify all of the
SUBADR parameters if you need to change any of them.
3. If the PROTOCOL parameter is specified, all the level 4 protocol identifiers used must be
specified (pre–existing identifiers can not be skipped).
———————————————————————————————————————
7831 5470–200

Section 7
X.25 PSCS Troubleshooting
This section provides troubleshooting information for the X.25 PSCS program product.
Section Topic
7.1 Troubleshooting Overview
7.2
7.2.1
7.2.1.1
7.2.1.2
7.2.1.3
7.2.2
7.2.2.1
7.2.2.2
7.3
7.3.1
7.3.2
7.3.3
7.3.3.1
7.3.3.2
7.3.3.3
7.4
7.4.1
7.4.1.1
7.4.1.2
7.4.1.3
7.4.2
7.4.2.1
7.4.2.2
7.4.2.3
Verifying Line Operation
Verifying General Line Operation
Determining If X.25 PSCS Installation Failed
Determining If X.25 PSCS Initialization Failed
Determining If Hardware/DCP System Resources Failed
Verifying Specific Line Operation
Physical Layer Connection
Link Layer Connection
Verifying Virtual Circuit Connections
Using Data Session or Service Operation to Verify Connections
Using NMS Commands to Verify Connections
Connection Troubleshooting Actions
Generating Telcon CENLOG Reports
Generating Layer 3/4 Platform Interface User Reports
Using Message Tracing
Verifying Message Data Transfer Performance
Identifying External Facilities and Interfaces That May Affect Data Transfer
Performance
Determining Adequate Virtual Circuit Connection Resources
Determining Whether Telcon or Host Interface Resources Affect Data
Transfer
Determining Adequate DCP/OS Resources
Determining Areas Within X.25 PSCS That Affect Data Transfer
Packet Level Characteristics
Incompatible Flow Control Values
Facility Constraints
Link Level Characteristics
Incompatible Frame Control Values
Subscription Parameters
Physical Line Characteristics
———————————————————————————————————————
7831 5470–200 7–1

X.25 PSCS Troubleshooting
7.1 Troubleshooting Overview
7–2
Areas that may require verification include X.25 PSCS line operation, virtual circuit
connections, and message data transfer performance. Before troubleshooting X.25
PSCS problems, ensure that:
• Any general Telcon problems, such as HCONFIG configuration errors and
warnings, or other Telcon component problems have been resolved
• Telcon is operational
• At least one X.25 LINE statement has been configured
———————————————————————————————————————
7831 5470–200

7.2 Verifying Line Operation
X.25 PSCS Troubleshooting
X.25 PSCS connection failures occur in both general and specific line operation.
To verify... You must determine if...
general line operation • X.25 PSCS installation failed
• X.25 PSCS initialization failed
• hardware and/or DCP system resources failed
specific line operation • physical layer connection failed
• link layer connection failed
———————————————————————————————————————
7.2.1 Verifying General Line Operation
This subsection provides information on verifying general line operation. It describes
symptoms found when none of the lines belonging to X.25 PSCS are operating. Line
disruption may signal one of the more general problems discussed in this section.
———————————————————————————————————————
7831 5470–200 7–3

X.25 PSCS Troubleshooting
7.2.1.1 Determining If X.25 PSCS Installation Failed
7–4
If X.25 PSCS does not appear to be working, verify that the product was properly
installed with Telcon. See the DCP Series Telcon Installation Guide (7831 5645) for
information on verifying Telcon and Telcon program product installation.
IF... THEN...
you started Telcon from a DCP/OS console in an interactive mode and
receive the following message:
where:
is a configured X.25 PSCS LINE name.
is the port address on which the line is configured.
you started Telcon from a DCP/OS console in an interactive mode and
receive the following message:
you have access to an NMS console, enter the command:
This command displays all program products installed with Telcon,
and their release levels.
X.25 PSCS is not
installed.
X.25 PSCS is installed.
verify that DCPX25-
PSCS Release Level 5Rx
is present in the
response.
———————————————————————————————————————
7831 5470–200

7.2.1.2 Determining If X.25 PSCS Initialization Failed
X.25 PSCS Troubleshooting
When the first configured PSCS line is enabled, it examines all configuration
statements pertaining to X.25 PSCS and constructs tables for internal use. If, during
the initialization process, an error is detected by X.25 PSCS, no lines are enabled. This
problem may be identified from the following:
IF... THEN...
you start Telcon from a DCP/OS console in
interactive mode and receive the following message:
where:
is a configured PSCS LINE name
is the port address on which the
line is configured
you have access to an NMS console and have
logged the CENLOG events, use the NMS LOGI
command to display the logged CENLOG events
you cannot locate the CENLOG "
" message
search for a Class 5, Event Code 15
CENLOG " "
from Procedure PDNIUS. Register R9
contains the specific reason for the
initialization error. Refer to the DCP Series
Telcon Message Manual (7436 0728) for
an explanation of the reason code.
search for a Class 5, Event Code 15
CENLOG " "
from Procedure PDNIUS. Register R9
contains the specific reason for the
initialization error. Refer to the DCP Series
Telcon Message Manual (7436 0728) for
an explanation of the reason code.
determine if hardware or DCP system
resources failed. See Section 7.1.1.3,
"Determining If Hardware/DCP System
Resources Failed."
———————————————————————————————————————
7831 5470–200 7–5

X.25 PSCS Troubleshooting
7.2.1.3 Determining If Hardware/DCP System Resources Failed
7–6
If you determine that a X.25 PSCS installation or initialization error is not the problem,
hardware or resources allocated by the DCP/OS may be the reason for the line failure.
To locate the problem:
• Verify that the line module type configured for the PSCS LINE is correct.
A port address that references the wrong line module cannot “load” the line
module or initialize X.25 PSCS. Refer to the DCP Series X.25 Packet Switched
Communications Software (PSCS) Software Release Announcement (7436 5289)
for a list of supported line module types.
• If you observe a slow response, do not see a response, or observe excessive mass
storage disk access when no other activity is occurring on the DCP, verify the
amount of memory available for the Telcon program.
When the first PSCS line is enabled, X.25 PSCS initializes by constructing internal
tables. The additional memory required during X.25 PSCS initialization may exceed
a DCP/OS memory limitation, causing a “throttling” condition. This condition
adversely impacts performance because DCP/OS is allocating more resources to
memory management than to the X.25 PSCS program for processing message data.
The DCP/OS provides console commands for:
• Examining the status of the DCP
• Determining the programs running on the DCP
• Examining memory usage
They include:
• @@CONS SS
• @@CONS RE
• @@CONS RD
• @@CONS RT
7831 5470–200

X.25 PSCS Troubleshooting
DCP/OS also provides a number of programs which allow you to examine and
modify the memory structure of the DCP. Refer to the DCP/OS Operations
Reference Manual (7831 5702) for a description of these commands and programs.
Memory problems may be identified by using a number of DCP/OS console
commands or programs.
See your Unisys representative to identify the amount of DCP system resources
required, such as memory requirements, and to determine whether current
resources are sufficient.
———————————————————————————————————————
7831 5470–200 7–7

X.25 PSCS Troubleshooting
7.2.2 Verifying Specific Line Operation
7–8
This section describes problems unique to a given line connection. From your Telcon
NMS console, ensure that the PSCS LINE is enabled by entering:
where:
is the name of the configured PSCS LINE.
Determine the status of the PSCS LINE by entering:
IF the response received is... THEN a problem exists with...
X.25 physical layer connection. See Section 7.2.2.1,
"Physical Layer Connection."
line designation. Ensure that the line is of type ,
then determine that the line is physically connected.
hardware components. Check the DCP line module,
modem, and connecting cable. You may have to
replace one or more of these items to determine the
failing component.
X.25 link layer service. See Section 7.2.2.2, "Link
Layer Connection."
———————————————————————————————————————
7831 5470–200

7.2.2.1 Physical Layer Connection
X.25 PSCS Troubleshooting
If the response is received, observe any messages displayed on the
interactive DCP/OS console if you have previously entered the NMS UP LINE
command. The following message may be displayed on the DCP/OS console:
where:
is the port number of the X.25 PSCS line.
is either “” or the name of another program running on the DCP.
IF the program name is... THEN...
the X.25 PSCS line is being enabled on an incompatible or broken
line module type. Refer to the DCP Series X.25 PSCS Software
Release Announcement (7436 5289) to verify that the correct line
module type is being used.
running on the DCP the system is attempting to enable the X.25 PSCS line on a port
that is already being used by the program.
Note: is the name used by DCP/OS itself.
———————————————————————————————————————
7.2.2.2 Link Layer Connection
A problem exists at the X.25 link layer service if the line status response displays:
7831 5470–200 7–9

X.25 PSCS Troubleshooting
7–10
To determine the cause:
Action Explanation
Verify the
DTE/DCE
assignment.
Verify the
network's
characteristics
compatibility.
Verify that the
PDN or X.25
device is
operational.
The line status response displays if the X.25 PSCS line is to emulate a
DTE, or if it is to emulate a DCE. If you have configured this line to connect
to a network, for example, the network is typically the DCE. If you have
configured this line to connect directly to another X.25 device in a back-to-back
fashion or to connect to an external DTE, you must decide which device
becomes the DTE and which becomes the DCE. If both the DCP and the X.25
device have been configured as either the DTE or DCE, the X.25 PSCS line will
not initialize.
Different link layer protocol methods are used to form a link layer connection. If
the network type that you configure uses a different method, the link may not
initialize.
Ensure that the line status displays the network name you have configured.
IF you have configured
this line to connect...
to one of the PDNs
supported by X.25 PSCS
directly to another X.25
device
THEN...
determine that the name configured on the
NETWORK parameter of the X25DEF statement
is correct for this PDN. If you have specified
the L2OPT parameter on the X25DEF
statement, verify that the option values chosen
do not conflict with those required by the PDN.
The L2OPT parameter values specified override
those implicitly defined by the NETWORK
parameter. Refer to Table 6–4, "NETID Values,"
in Section 6 of this guide.
determine that the network type specified is
compatible with the network being emulated by
the X.25 device. If no specific PDN emulation is
offered by the X.25 device, you must examine
each link layer option described by the X25DEF
statement's L2OPT parameter to determine
whether it should be set.
A software failure within the PDN or connected X.25 device may be the cause
of the line failure. Without contacting the PDN network administrator or
accessing the connected X.25 device, this symptom is not directly observable.
In this situation, it may be necessary to obtain an X.25 line monitor, connect it
to the X.25 PSCS line, and observe the line activity to determine this type of
failure. Finally, if you are using standard line modules, you may need to perform
a Telcon dump and analyze the port processor trace entries.
———————————————————————————————————————
7831 5470–200

7.3 Verifying Virtual Circuit Connections
X.25 PSCS Troubleshooting
After you have verified that one or more X.25 lines are operational, the lines can be
used for establishing packet-layer virtual circuit connections. These connections are
formed between X.25 DTE devices and the DCP using call type packets. Within the
DCP, an incoming call packet is routed to one of several layer 4 types, including such
program products as OSITS, TCP-IP Stack, or SNA/net. The DTE device can be
attached to a PDN where the network is used for routing the connection, or it can be
directly attached to the DCP. If you have configured the DCE Network feature for
connection routing, the virtual circuit can connect to a layer 4 that resides within
another DCP. Refer to Section 2, “Configuring Standard X.25 PSCS Capabilities,” and
Section 3, “Configuring a DCE Network,” for information on standard X.25 PSCS and
DCE Network feature connection concepts.
Note: Permanent virtual circuit (PVC) connections do not use call type packets.
Routing is explicitly defined with DTE and DTETYPE statements. The DCE
Network feature does not support permanent virtual circuits.
The following subsections describe methods for verifying whether virtual circuit
connections were established and determining circuit connection troubleshooting
actions.
———————————————————————————————————————
7.3.1 Using Data Session or Service Operation to Verify
Connections
You can verify virtual circuit connection establishment based upon the operability of
the data session or operability of the service provided by the layer 4 entity. For
example, if the connected DTE device is able to achieve a data session with a host,
establishment of the virtual circuit connection is verified. However, not being able to
achieve the data session does not imply that the virtual circuit connection was not
established. The problem may be related to the layer 4 service.
———————————————————————————————————————
7.3.2 Using NMS Commands to Verify Connections
Enter the following NMS command to display a message that includes the number of
active virtual circuits:
where:
is a configured PSCS LINE name.
7831 5470–200 7–11

X.25 PSCS Troubleshooting
7–12
The following message appears:
where:
is the total number of active switched virtual circuits on the line.
is the total number of configured switched virtual circuits on the PDNGRP
statement.
is the total number of active permanent virtual circuits on the line.
is the total number of configured permanent virtual circuits on the PDNGRP
statement.
If the total number of active virtual circuits is not what you expect, use the following
NMS commands to provide more detailed information:
Command Description Explanation
LIST LINE=name Specifies the X.25 line on
which you want status
information.
STAT PDTE=identifier Specifies a DTE on which to
display status information.
The response displays detailed
information for each active virtual circuit.
This information includes the:
• logical channel number
• DTE name or address to which it
belongs
• state of the circuit
• layer 4 type to which it belongs
is the configured DTE
statement name or the DTE address.
Refer to Section 5, “Using Network Management Services (NMS) Commands,” for
additional information on these commands.
———————————————————————————————————————
7831 5470–200

7.3.3 Connection Troubleshooting Actions
X.25 PSCS Troubleshooting
If, from the layer 4 connection or service operation or from the NMS command
display, you determine that the desired virtual circuit connections are not established,
use the following actions. Every failed attempt to establish a virtual circuit connection
is reported, including the reason for the failure.
———————————————————————————————————————
7.3.3.1 Generating Telcon CENLOG Reports
X.25 PSCS uses the Telcon CENLOG mechanism for reporting cleared virtual circuit
connections. Each CENLOG contains a unique supplementary text string which
identifies the reason for the CENLOG. CENLOGs also include a diagnostic code within
a register (Rn) to determine the reason the virtual circuit was cleared. The
supplementary text strings related to cleared virtual circuits are:
•
•
•
• (for PVC-types only)
In addition to the preceding CENLOG events, other CENLOGs that are related to the
cleared virtual circuit may be reported. Other CENLOGs may report a configuration
error and can be used to determine why connection establishment failed.
Refer to the DCP Series Telcon Message Manual (7436 0728) for a description of
CENLOG events that are reported by X.25 PSCS. The Telcon Message Manual also
includes a description of the X.25 PSCS diagnostic codes accompanying the CENLOG
events.
———————————————————————————————————————
7831 5470–200 7–13

X.25 PSCS Troubleshooting
7.3.3.2 Generating Layer 3/4 Platform Interface User Reports
A layer 4 feature within X.25 PSCS, or a program product using X.25 PSCS that
initiates virtual circuit connections, always receives a notification about the success or
failure of the connection attempt. The Layer 3/4 Platform interface service returns a
Clear primitive to the layer 4 feature or product when the attempt fails. The Clear
primitive includes a cause and diagnostic code (also reported by the CENLOGs).
Depending upon the layer 4 feature or product you are using, these codes can be
reported to you directly or they can be translated by the feature or product into an
error message.
The cause code can help you determine where the connection attempt failed.
Cause Code
(Decimal)
Meaning Explanation
19 Local procedure error The PDN's DCE node attached to the DCP is failing
the attempt.
17 Remote procedure error The DTE being called is rejecting the connection
attempt.
Neither — Refer to DCP Series Telcon Message Manual (7436
0728).
The diagnostic code can also help you determine where and why the connection
attempt failed. Refer to the DCP Series Telcon Message Manual (7436 0728) for a
description of the X.25 PSCS diagnostic codes accompanying the CENLOG events.
———————————————————————————————————————
7.3.3.3 Using Message Tracing
7–14
You can generate a trace that shows the path of a failed virtual circuit attempt with
NMS TRAC SNAP=X25 commands. Refer to Section 5, “Using Network Management
Services Commands,” for a description of the command. If you are using the DCE
Network feature, enable message tracing with the
TRAC SNAP=DCEF command.
Note: You must activate all interfaces affecting the PDNCALL module using the
TYPE=H parameter value for the TRAC SNAP=X25 command to process call
packets for virtual circuit establishment.
———————————————————————————————————————
7831 5470–200

7.4 Verifying Message Data Transfer
Performance
X.25 PSCS Troubleshooting
This subsection describes areas that can affect message data throughput and the
conditions that may occur when performance is adversely impacted. Usually,
performance can be verified at the session data layer. If your console sends prompt
message responses or if data transfers that are larger than the expectations of the
session layer running over an X.25 network are sent, further verification is not
warranted. (See your Unisys representative for expected data message throughput
values when running various session layer protocols over an X.25 network.) If
expected throughput is not occurring, refer to the following information.
———————————————————————————————————————
7.4.1 Identifying External Facilities and Interfaces That May
Affect Data Transfer Performance
Several external software and hardware conditions may adversely impact the message
data throughput in X.25 PSCS. They include virtual circuit connection resources,
Telcon or host interface resources, and DCP/OS resources.
———————————————————————————————————————
7.4.1.1 Determining Adequate Virtual Circuit Connection Resources
The virtual circuit connections established through X.25 PSCS require resources
outside the DCP. If the DCP is not active, it may be waiting for responses from other
resources. Resources include:
• Public or private X.25 network
Typically, an X.25 network provides virtual circuit connections for many users.
One or more of the network's routing nodes may be congested from excessive
message data from users.
• Remote DTEs
Remote DTE devices may not have sufficient software or hardware resources to
accommodate the demand from the virtual circuit connections of the DCP.
7831 5470–200 7–15

X.25 PSCS Troubleshooting
Verifying in a production environment that these resources adversely impact
performance can be difficult. If it is unreasonable to isolate or remove the impact of
the network or remote DTE, use the following tools to determine performance impact:
Tool Description
Message Tracing Use the NMS TRAC SNAP=X25 command to enable message buffer
tracing at the level 2/3 interface. Refer to Section 5 for a description of
the command. For each data message (or packet) sent or received, the
contents of the trace file includes the DCP real-time clock. By analyzing
the real-time clock values, the response time between message or
packet exchanges by the network, or subsequently from the remote
DTE, can be determined. An excessive delay can suggest that the
performance impact is associated with the X.25 network or remote DTE.
Receipt of Receive-Not-Ready (RNR) packets also indicate a resource
condition.
X.25 Line Monitor By attaching a monitor to the line between the DCP and the network, the
message data or packet response time can be determined. The line
monitor also shows link level RNR frames being received, indicating a
network resource condition.
———————————————————————————————————————
7.4.1.2 Determining Whether Telcon or Host Interface Resources Affect
Data Transfer
7–16
X.25 PSCS provides a number of interfaces to Telcon modules which can “terminate”
the X.25 circuit connections or relay them to a configured host. These interfaces
introduce other resources that can adversely impact performance. A Telcon or host
interface can be slow to respond or send message data to X.25 PSCS, even if X.25
PSCS is operating properly.
These interfaces may provide their own tracing tools for determining operating
efficiency. In addition, you can use the NMS TRAC SNAP=X25 message tracing
command to determine message response characteristics by enabling the message
tracing command for the layer 3/4 interface and analyzing the message trace file's realtime
clock values.
———————————————————————————————————————
7831 5470–200

7.4.1.3 Determining Adequate DCP/OS Resources
X.25 PSCS Troubleshooting
As more virtual circuit connections are formed, more resources are needed for each
connection's table space. If the additional table space needed approaches the amount
of memory available to the DCP/OS, a DCP “throttling” condition can occur. This
condition adversely impacts performance because DCP/OS is allocating more
resources to memory management than to X.25 PSCS for processing message data.
The DCP/OS provides console commands for:
• Examining the status of the DCP
• Determining what programs are running on the DCP
• Examining memory usage
They include:
• @@CONS SS
• @@CONS RE
• @@CONS RD
• @@CONS RT
DCP/OS also provides a number of programs which allow you to examine and modify
the memory structure and use of the DCP. Refer to the DCP Series Distributed
Communications Processor Operating System (DCP/OS) Operations Reference
Manual (7831 5702) for a description of these commands and programs.
———————————————————————————————————————
7831 5470–200 7–17

X.25 PSCS Troubleshooting
7.4.2 Determining Areas Within X.25 PSCS That Affect Data
Transfer
The following X.25 PSCS components may adversely impact performance.
———————————————————————————————————————
7.4.2.1 Packet Level Characteristics
X.25 PSCS data transfer at the packet level may be impacted by:
• incompatible flow control values
• facility constraints
———————————————————————————————————————
Incompatible Flow Control Values
7–18
For each virtual circuit connection, window and packet size flow control values are
assumed or are negotiated during the establishment of the connection. If the values
between X.25 PSCS and the network are not the same, a large overhead is incurred
while the connection is being repeatedly reset, or cleared and reestablished.
X.25 PSCS uses Class/Event 13/3 CENLOGs for reporting Reset and Clear packets sent
to or received from the network. Use an NMS console to observe these CENLOG
events, or analyze the CENLOG file to which they are being sent. X.25 PSCS uses the
following supplementary text strings for reporting these events:
•
•
•
•
Refer to the DCP Series Telcon Message Manual (7436 0728) for a description of
CENLOG events.
———————————————————————————————————————
7831 5470–200

Facility Constraints
X.25 PSCS Troubleshooting
If facilities such as small packet size or optional throughput class, transit delay, or low
priority are used, their values may cause poor performance. These facilities can be
assumed or negotiated on a per call basis between X.25 PSCS and the network.
You can use the NMS TRAC SNAP=X25 command to trace the facilities used during
the establishment of a connection. If no facilities are negotiated during the connection
set up, X.25 PSCS assumes any values configured on any associated DTE or DTETYPE
statements. Consult your network administrator for the PDN facility values you have
subscribed.
———————————————————————————————————————
7.4.2.2 Link Level Characteristics
Network parameter attributes that you can define on the X25DEF statement or that
are provided when you specify a network type on the X25DEF statement's NETWORK
parameter may affect data transfer. Adverse performance impacts at the link level may
be difficult to observe, depending upon the attributes defined for the network.
CENLOG events may or may not be reported for various problems due to attribute
incompatibilities. An X.25 line monitor may be necessary for analyzing frame
exchanges between X.25 PSCS and the network to determine optimum performance.
———————————————————————————————————————
Incompatible Frame Control Values
Window and frame sizes are assumed between X.25 PSCS and the network. If these
values are incompatible, a large overhead is incurred when the link level periodically
reinitializes. Incompatible flow control values are observed with Class/Event 14/2
CENLOG events containing the following supplementary text strings:
•
•
•
Depending on how the network definition's level 2 parameter 16 (X25DEF statement
parameter value L2OPT=16) is set, an incompatibility could affect all virtual circuit
connections on the line. In this case, symptoms described in Section 7.4.2.1, “Packet
Level Characteristics,” also appear.
———————————————————————————————————————
7831 5470–200 7–19

X.25 PSCS Troubleshooting
Subscription Parameters
Values for subscription parameters such as frame size (N1), frame response timer
(T1), retransmission counter (N2), and idle condition timer (T3) can have an adverse
affect on performance.
frame size, response time
value, or retransmission
counter are incompatible
IF... THEN...
a large overhead is incurred in the link level procedure in order
to recover from invalid frame sizes received, from discarding
unexpected frames, or from reinitializing the link.
retransmission counter expires a CENLOG event with is reported.
idle condition timer expires the link level is reinitialized which may clear all virtual circuits.
———————————————————————————————————————
7.4.2.3 Physical Line Characteristics
7–20
At the physical level of the X.25 connection, no characteristics are directly controllable
by X.25 PSCS. The line bandwidth, or speed, is the largest line factor affecting
performance. The SPEED parameter on the LCLASS statement does not control the
actual line speed or baud rate running on the line. This is controlled by the baud rate
setting on the modem connected to the line module. Check the modem's baud rate
setting to verify the line speed; no warning messages are reported to indicate any
incompatibilities between this setting and the speed specified on the SPEED
parameter.
Note: For ILM-20s, the SPEED parameter is particularly critical. Its value must
match the cumulative setting values of the (up to four) modem line speeds.
If the line quality is poor, a large overhead may be incurred from corrupted frames
(frames with bad frame check sequences [FCSs]) or aborted frames (frames containing
flags). These errors cause the link level to resend frames or reinitialize the link. These
symptoms are indicated by a Class/Event 15/2 CENLOG event with a “ ” or
“ ” supplementary text string. Poor line quality also causes symptoms
described in Section 7.4.2.2, “Link Level Characteristics.” If no symptoms are observed,
connect an X.25 line monitor between X.25 PSCS and the network to analyze frames
with a bad FCS or frames that have been aborted.
———————————————————————————————————————
7831 5470–200

Appendix A
X.25 PSCS Reserved Words
Certain words have special meaning to Telcon or X.25 PSCS. Therefore, do not use
these words in a configuration statement name field. Words reserved for X.25 PSCS
are listed below. Words reserved for Telcon are listed in the DCP Series Telcon
Configuration Reference Manual (7831 5686).
ABBRVADR
ACKDATA
ACCUNET
AIRNET
ALLOWI
ALLOWIO
ALLOWO
ARINC
ARPAC
AUSTPAC
BX25
CALLED
CALLING
CLOSED
DAD
DATAPAC
DATEXPA
DCECUG
DCENODE
DCPNET
DCS
DDNX25
DESTID
DNICID
DN1
EXTENDED
FASTSL
FASTSLA
FIXED
FLOWC
HGROUP
HIPRI
IBERPAC
IN
PSCS Reserved Words
IPOSI
IPTCP
ITAPAC
MEXPAC
MIXED
MLP
NOCHG
NPDN
PADVTX
PDN
PDNDXA
PDNELLC
PDNIPID
PDDNNET
PDDNPID
PDNQLLC
PDNTRUNK
PDNUNIS
PDNUPID
PDNX28
PERM
PLS
PLSTSU
PSCSNET
PSS
PVC
RIC
ROC
RPOA
RRVCHG
RVCHG
SITA
SVC
TELENET
TELEPAC
TELEPACP
THRUCLAS
TPCCITT
TPOSI
TRANDLY
TRANSPAC
VIDEOTEX
XNET
X25NET
X25PKT
X28PAD
X29PAD
X75
Note: To obtain the most current list of reserved words, run the configuration
processor with the option ().
——————————————————————————————————————
7831 5470–200 A–1

Appendix B
X.25 PSCS Outgoing Call Routing
Concepts
This appendix explains X.25 PSCS call routing concepts. Specifically, it explains how
X.25 PSCS routes outgoing calls to the correct line and network. This information may
help you make informed configuration decisions.
This appendix provides information on standard X.25 PSCS call routing only. It does
not discuss DCE Network routing.
Note: This appendix includes discussions about when to use DTE statements to
provide X.25 PSCS with routing information and when this information is
not required. Some DTEs must always be configured, however. That is, they
must always be defined by DTE statements. For example, if another DCP is
to function as a DTE, it must be defined by a DTE statement even if X.25
PSCS does not require the statement for routing purposes. As well, these same
DTEs cannot use the abbreviated address option described on these pages. See
the discussion on the DTE statement presented in Section 6, “Using X.25
Configuration Statements,” for more information.
Routing outgoing calls requires X.25 PSCS to determine the correct network and line
to which outbound packets should be delivered. In some configurations, you do not
have to configure DTE statements. In others, you must. The following information
helps you determine when to configure DTE statements and when this is not
necessary.
———————————————————————————————————————
7831 5470–200 B–1

X.25 PSCS Outgoing Call Routing Concepts
When DTE Statements Are Not Necessary
There are four types of configurations that do not require DTE statements for outgoing
calls. In these instances, when you configure a basic connection to a network, you
provide all the information X.25 PSCS requires to correctly route calls. These
configurations are:
• A DCP connected to a single network by a single line.
• A DCP connected to a single network by more than one line, but the particular
line to which the call is routed does not matter.
• When a Level 4 program initiating the call is able to scan the configuration and
determine the correct line or network. The TCP-IP Stack and the Internet Protocol
component (OSITP) of the OSITS program product are the only Level 4 programs
Unisys provides with this capability, though some user-written Level 4 programs
may include it as well.
• When the Level 4 program can be configured to specify the desired line or
network. The PSCS X.28/PAD feature and the Transport Protocol component
(OSITP) of the OSITS program product have this capability. That is, configuration
statements or parameters other than the DTE statement can be used for providing
routing information.
———————————————————————————————————————
Configuring Routing Information
B–2
Except for the configurations just described, all others require you to supply outgoing
call routing information in the configuration. You provide this information on DTE
statements, and you can provide it in one of two ways:
• You can configure each DTE with a DTE statement.
• You can define some or all DTEs on the same network with a single DTE
statement. (You cannot, however, define DTEs on different networks with the
same DTE statement.)
In both instances, X.25 PSCS uses a packet's called (destination) DTE address to
determine the correct network on which to place the call.
7831 5470–200

X.25 PSCS Outgoing Call Routing Concepts
When you define each DTE with its own statement, X.25 PSCS attempts to match the
packet's entire called DTE address with an entry on a list of addresses compiled from
DTE statements. When it finds a match, it references the associated PDNGRP
statement. Through the PDNGRP's reference to an X25DEF statement, X.25 PSCS
determines the network on which to route the call. This method does not define a
particular line to use, only the network. To define a particular line, you must also
specify on the DTE statement; X.25 PSCS then routes all calls to the
defined DTE on the line associated with the PDNGRP statement.
Defining each DTE with its own DTE statement is efficient for networks with few
DTEs. However, when the DCP must communicate with many DTEs, or when DTEs
may be added to the configuration periodically, defining many with the same
statement may be more efficient.
Define more than one DTE by specifying a DTE statement with the abbreviated
address option () and by entering a partial address on the
DTEADR parameter. The ABBRVADR parameter tells X.25 PSCS that the address on
the statement is a subset of the full address. X.25 PSCS then matches this partial
address with the most significant digits of a packet's called DTE address, not with the
entire DTE address.
For example, if you used the DNIC as the partial address, X.25 PSCS can route calls to
any DTE on the network, since each network DTE has an address beginning with
these four digits. As with configured DTEs, to select a particular line, specify the
FIXED option.
If X.25 PSCS cannot match a packet's called DTE address with one on its list of DTE
statements, it cannot place the call.
Figure B–1 illustrates how X.25 PSCS determines the line and network on which to
route outgoing calls.
7831 5470–200 B–3

X.25 PSCS Outgoing Call Routing Concepts
B–4
Figure B–1. Outgoing Call Routing
———————————————————————————————————————
7831 5470–200

Appendix C
NMS TRAC Command Trace File
Formats
This appendix outlines NMS TRAC command trace file formats.
Section Topic
C.1 SNAP=X25 Parameter Option Format
Example
C.2 SNAP=DCEF Parameter Option Format
Example
———————————————————————————————————
7831 5470–200 C–1

NMS TRAC Command Trace File Formats
C.1 SNAP=X25 Parameter Option Format
C–2
This section describes the contents of the trace files generated by the NMS TRAC
SNAP=X25 parameter option.
Word Offset Description
0
1
2-3
4
5
6-7
8-9
10-n
Record length in bytes.
Trace return virtual address.
DCP real-time clock value.
DATA parameter value of the interfaces to trace. This corresponds to the
TYPE=H parameter option used in conjunction with the DATA parameter value
setting.
DATA parameter value of items being traced. This corresponds to the TYPE=M
parameter option used in conjunction with the DATA parameter value setting.
Interface identifier in ASCII.
Item identifier in ASCII.
Data of item being traced. "n" depends on the item type being traced. For
example, if Registers are being traced (identifier equals ), the data uses 16
words (one word per register). "n" equals 25 decimal (9+16).
Note that any other selected item identifiers follow the end of the preceding data item
starting on the next eight-word boundary.
———————————————————————————————————
7831 5470–200

Example
NMS TRAC Command Trace File Formats
The following is an example of a trace entry. The output was generated using the
DPRINT utility program. For information on how to use the DPRINT program or the
DCP/OS @LIST command for printing trace entries, see the DCP Series Distributed
Communications Processor Operating System (DCP/OS) Operations Reference
Manual (7831 5702).
When using the DPRINT program on an OS 2200 host, you must first transfer the
omnibus trace file from its DCP file to an OS 2200 host file (or file element). The
DCP/OS @COPY command or the Telcon NMS XFER command allows you to do this.
For information on the @COPY command, see the DCP Series Distributed
Communications Processor Operating System (DCP/OS) Operations Reference
Manual (7831 5702). For information on the XFER command, see the DCP Series
Telcon Operations Reference Manual (7831 5728).
Word Offset
(Hex.) Trace Data ASCII Equivalent
Note: 1. When registers are being traced (identifier equals ), the register values
are stored in the order R1 through R15 and R0.
2. When the MCT is being traced (identifier equals MCT), only the last half
of PCALL packet area is included.
3. When the message buffer is being traced (identifier equals ), up to 128
bytes of data are traced starting at the offset in field .
———————————————————————————————————
7831 5470–200 C–3

NMS TRAC Command Trace File Formats
C.2 SNAP=DCEF Parameter Option Format
C–4
This section describes the contents of the trace files generated by the NMS TRAC
SNAP=DCEF parameter option.
Word Offset Description
0
1
2-3
4-5
6-n
Record length in bytes.
Trace return virtual address.
DCP real-time clock value.
Trace identifier in ASCII.
Data of item being traced. "n" depends on the item type being traced.
For example, if the PCALL packet is being traced at one of the
interfaces, such as input from level 4 (identifier equals L4PI), the data
occupies 64 words (size of MCT). "n" equals 69 decimal (5+64).
Note that the next trace entry follows the end of the preceding trace entry starting on
the next 128-byte boundary.
———————————————————————————————————
7831 5470–200

Example
NMS TRAC Command Trace File Formats
The following is an example of a trace entry. The output was generated using the
DPRINT utility program. For information on how to use the DPRINT program or the
DCP/OS @LIST command for printing trace entries, see the DCP Series Distributed
Communications Processor Operating System (DCP/OS) Operations Reference
Manual (7831 5702).
When using the DPRINT program on an OS 2200 host, you must first transfer the
omnibus trace file from its DCP file to an OS 2200 host file (or file element). The
DCP/OS @COPY command or the Telcon NMS XFER command allows you to do this.
For information on the @COPY command, see the DCP Series Distributed
Communications Processor Operating System (DCP/OS) Operations Reference
Manual (7831 5702). For information on the XFER command, see the DCP Series
Telcon Operations Reference Manual (7831 5728).
Word Offset
(Hex.) Trace Data ASCII Equivalent
Note: 1. When registers are being traced (identifier equals ), the register
values are stored in the order R0 through R15.
2. When the PCALL packet is being traced (identifier equals ), the
complete MCT is included.
3. When the message buffer is being traced (identifier equals ), the first
16 bytes of data traced start at the beginning of the message buffer (
header). Up to 112 (128-16) bytes of data are then traced starting at the
offset in field .
———————————————————————————————————
7831 5470–200 C–5

Glossary
A
asynchronous transmission
A transmission mode for serial data channels. The sender and receiver achieve bit
synchronization by operating the channel at a specified frequency and byte
synchronization by inserting start and stop signals into the data stream before and
after each character. This mode is called asynchronous because there is no
synchronizing clock between sender and receiver.
C
call request
A control packet used to establish a network connection across a packet-switched
PDN. The call request packet contains addressing information and optional special
network facility requests such as requests for reverse charging, nondefault packet and
window sizes, and closed user groups.
CCITT
See International Telecommunications Union/Telecommunications Standardization
Sector.
CENLOG
See critical event notification and logging.
closed user group (CUG)
A security scheme that groups terminals and hosts. Members of the CUG can
communicate with each other but cannot communicate with terminals and hosts
outside the group. A device may belong to more than one CUG.
cluster controller
A hardware component that concentrates communication traffic to and from
workstations attached to it, and that centrally manages the memory and peripheral
resources of the terminal system or workstation.
7831 5470–200 Glossary–1

Glossary
COMUS
Acronym for Computerized Onsite Maintenance of User System. COMUS is an
OS 1100 processor that leads you interactively through the process of defining the
configuration and parameters for the software products you want to install. For
example, after you define a CMS 1100 configuration, COMUS calls the symbolic stream
generator, which creates a runstream to generate a CMS 1100 configuration file.
COMUS can also initiate generation of the Telcon software for DCPs in your network.
Consultative Committee on International Telephone and Telegraph (CCITT)
See International Telecommunications Union/Telecommunications Standardization
Sector.
critical event and notification logging (CENLOG)
The facility that allows software processes to log system and error events. Logs are in
a standard format and can be written to a disk file cataloged for that purpose. In
addition, warning messages are sent to network administrator consoles for critical
events.
CUG
D
DAD
See closed user group.
See directly attached DTE.
data circuit-terminating equipment (DCE)
A network switch that communicates with customer equipment (a computer or
terminal). X.25 defines how a DCE (network equipment) communicates with a DTE
(subscriber equipment).
data network identifier code (DNIC)
An international prefix for a recognized X.25 network, as defined by ITU/TSS
Recommendation X.121.
data terminal equipment (DTE)
An X.25 term describing a network subscriber's computer or terminal that
communicates with a network switch. X.25 defines communication between a DTE
(subscriber equipment) and DCE (network equipment).
Glossary–2
7831 5470–200

Glossary
data unit control (DUC)
The portion of a transport network control region that segments port data units into
network data units and controls network flow. This function implies the reassembly of
network data units into port data units and the sequencing of the network data units.
DCA
See Distributed Communications Architecture.
DCA transport protocol (DTP)
The DCA (Level II) layer 4 protocol that defines the set of rules for creating and
maintaining end-to-end communication paths between computing systems or transport
service users. It establishes and terminates connections, controls data flow, recovers
errors, and segments and recombines messages. DTP replaced port flow control and
the Device Management Facility (DMF), which are functions supported by DCA Level
I. Handles all DCA layer 4 traffic between DCA layer 3 modules (such as DNS or
TSTN) and DCA layer 5 modules (such as DTPX).
DCA transport protocol extension (DTPX)
The DCA level II layer 5 protocol that establishes and controls interactive sessions,
session layer addressing, and data assurance. Handles all DCA layer 5 traffic between
the DCA layer 4 modules (such as DTP) and a VTR (via TSM) or End-User Module (via
EUSERV).
DCE
See data circuit-terminating equipment.
DCE Network feature
An X.25 PSCS feature that enables Telcon networks to function as private packet
networks. This feature enables directly attached DTEs to use the X.25 protocol to
access the Telcon network for communications with other DTEs.
DCP
DDN
See Distributed Communications Processor.
See Defense Data Network.
7831 5470–200 Glossary–3

Glossary
DDN 1100
A communication software product that provides OS 1100 host application system
services for the TCP/IP network environment of the Defense Data Network (DDN).
Defense Data Network (DDN)
An X.25 LAN-based connectionless packet-switched network operated by the U.S.
Department of Defense. The DDN is a telecommunications carrier service that
supports a large system of interconnected military and research networks, commonly
called Internet.
directly attached DTE (DAD)
A DTE that is physically cabled directly to the DCP and not connected to the DCP
through an intervening packet-switched network. DAD is used in conjunction with the
DCE Network feature, which provides routing from one external DTE to another
external or internal DTE. In this context, external DTEs are typically DADs.
Distributed Communications Architecture (DCA)
A Unisys proprietary network architecture and set of communication protocols based
on the seven-layer Reference Model for Open Systems Interconnection. DCA supports
the protocols required for several different network environments to interoperate. The
main differences between DCA and OSI architecture are in protocol implementation.
DCA software implementations allow integration and concurrent operation of
appropriate protocol modules or protocol conversion software that provide functions
required in OSI, TCP/IP, and other network environments.
Distributed Communications Processor (DCP)
A special-purpose computer designed exclusively for communication applications. The
DCP is used as a front-end processor for OS 1100 computers, or to interconnect
networks of OS 1100 computers and other machines. Depending on how it is
configured, a DCP can function as a remote concentrator, a message-switch (or nodal)
processor, or a front-end processor. DCPs are available in several models.
DNIC
DTE
Glossary–4
See data network identifier code.
See data terminal equipment.
7831 5470–200

DTP
DTPX
DUC
E
See DCA transport protocol.
See DCA transport protocol extension.
See data unit control.
external DTE
See directly attached DTE.
F
Glossary
Federal Information Processing Standards (FIPS)
The standards issued by the National Institute of Standards and Technology (NIST) for
use by the federal government. These standards pertain to particular aspects of data
processing. FIPS are usually based on international standards developed by ISO or
ITU/TSS.
FEP
FIPS
See front-end processor.
See Federal Information Processing Standards.
foreign host
A host manufactured by a company other than Unisys.
frame
A formatted unit of data or information prepared in the data link layer (layer 2) and
sent between stations. A frame can be either a control frame or a data frame. A frame
begins with a header and terminates with a frame check sequence.
7831 5470–200 Glossary–5

Glossary
front-end processor (FEP)
A communication computer associated with a host computer. It can perform line
control, message handling, code conversion, error control and application functions
such as control and operation of terminals. The function of the FEP is to offload the
communication-related functions from the host.
G
GOSIP
See Government Open Systems Interconnection Profile.
Government Open Systems Interconnection Profile (GOSIP)
An OSI implementation profile, released in 1988, for government use. This profile
defines sets of OSI protocols that can operate in various networks. GOSIP has been
mandated by the National Institute of Standards and Technology (NIST) as a federal
information processing standard (FIPS). The Central Computer and
Telecommunications Agency (CCTA) released a similar document for the United
Kingdom, the Government Open Systems Interconnection Procurement (U.K. GOSIP).
H
HDLC
See high-level data link control.
high-level data link control (HDLC)
A data link layer protocol defined by ISO for controlling the flow and transmission
errors of data being transmitted across a physical link. ITU/TSS modified HDLC to
create the link access procedure (LAP) and link access procedure, balanced (LAPB).
host
Glossary–6
A medium to large central processor attached to a network. Also referred to as an end
system. The host is generally dedicated to data processing functions, such as
executing application or system programs, rather than data communication functions.
Architecturally, there is no distinction between a DCA host and a DCA terminal
because both contain a termination system, although of vastly differing powers. In
SNA, a host is defined as an SNA node that contains a PU Type 5.
7831 5470–200

Glossary
hunt group
An optional X.25 facility which distributes incoming calls having an address associated
with the hunt group across a designated grouping of DTE/DCE interfaces.
I
IEEE
See Institute of Electrical and Electronics Engineers.
Information Services for personal computers (IS-PC)
An Information Services (IS) product for Personal Workstation 2 or PC systems
attached to DCA networks, X.25 PDNs, and 802.3 LANs. PW 2 or PC systems with IS
software installed can access DDP and DIS 1100 facilities, demand (interactive) and
Transaction Processing (TIP) facilities, and other application systems on an OS 1100
host. IS software also provides Distributed Data Processing (DDP) interoperability
with other PW 2 or PC systems, U Series systems, and USERNET 2 LAN systems
operating in a Telcon DCA network.
Institute of Electrical and Electronics Engineers (IEEE)
An international organization that promotes cooperation and exchange of information
among its members. IEEE technical committees develop and propose computer
standards, such as the 802 series standards, which define physical and data link
protocols for communication networks.
internal DTE
A DTE that terminates in the DCP or in a host through a DCP interface. An internal
DTE is on the Level 4 programs known to X.25 PSCS. This term is used in conjunction
with the DCE Network feature, which provides routing from an internal DTE to an
external DTE (DAD). See also directly attached DTE (DAD).
International Standards Organization (ISO)
The English language name for the Organization Internationale de Normalisation, an
agency that establishes international standards for communication network
architecture. Its basic Open Systems Interconnection (OSI) Reference Model divides
network functions into seven logical layers. Membership in the ISO is by country.
More than 90 countries currently participate. The ISO is supported by
telecommunications industry associations. Its activities are carried out by user
committees and manufacturers. The American National Standards Institute (ANSI) is
the U.S. group that is a member of the ISO.
7831 5470–200 Glossary–7

Glossary
International Telecommunications Union/Telecommunications Standardization Sector
(ITU/TSS)
An international advisory committee that establishes worldwide communication
recommendations (standards) for use by telecommunications authorities. Voting
members are nations, which often designate their administrations as representatives,
and other government groups such as the National Institute of Standards and
Technology (NIST). Nonvoting members are often standards organizations. Formerly
known as the Consultative Committee on International Telephone and Telegraph
(CCITT).
ISO
IS-PC
ITU/TSS
L
LCN
See International Standards Organization.
See Information Services for personal computers.
See International Telecommunications Union/Telecommunications Standardization
Sector.
See logical channel number.
line module (LM)
The hardware in the DCP that terminates serial communication lines, host channel
connections, and peripheral connections.
line switch module (LSM)
A module that physically connects the lines that run from the operating and backup
front-end processors (FEPs) to the terminals. If the operating FEP fails, the LSM
switches the communications lines to the backup FEP so data transmission can
continue. Used to switch lines from one DCP to another DCP, either under Software
Resiliency Control (SRC) or operator control through an NMS command.
link
LM
Glossary–8
The physical interconnection between two nodes in a network. It can consist of a data
communication circuit or a direct channel (cable) connection.
See line module.
7831 5470–200

Glossary
logical channel
A network user operating through a public data network at the network interface of a
set of session paths or logical subchannels. These subchannels are logical in that their
physical equivalent may change, depending on when they are used. DCA uses logical
subchannels to define the session path between the termination system and transport
network.
logical channel number (LCN)
A number that refers to a virtual circuit.
LSM
M
See line switch module.
mixed trunk
A trunk comprised of a combination of UDLC and X.25 lines.
multilink trunk
A trunk that utilizes the X.25 multilink options for data delivery on more than one line.
N
NDU
network
See network data unit.
A group of hardware and software components that are physically and logically linked,
and that interact according to established protocols. Network functions are
determined by the types of cooperating application systems within the network.
network data unit (NDU)
The unit of information into which the port data unit is segmented to satisfy the
resource handling requirements of the transport network.
7831 5470–200 Glossary–9

Glossary
Network Management Services (NMS)
The group of network control and reporting functions that establishes, maintains, and
modifies the operations of the Telcon communication network. NMS supports network
administration through persons or programs that maintain the operational capabilities
of the network. NMS is subdivided into a hierarchy of control points. The network
control ports are linked to the Applications Management System (AMS) ports through
a preestablished session path to control the total network. NMS commands are the
Telcon equivalent of the CMS 1100 communication system administrator (CSA)
commands.
NMS
O
See Network Management Services.
Open Systems Interconnection (OSI)
An ISO communication standard network protocol. OSITS is one of the program
products from the Open Systems products available for Telcon. Enables the computer
system of multiple vendors to communicate. OSI is based on standard protocols
developed by ISO and defined in the ISO Reference Model (usually called the OSI
model, as opposed to the TCP/IP model). OSI architecture has seven layers: physical
layer (layer 1), data link layer (layer 2), network layer (layer 3), transport layer (layer
4), session layer (layer 5), presentation layer (layer 6), and application layer (layer 7).
Each layer has specific functions, communicates with peer entities (those in the same
layer), performs services for the next higher layer, and requests services from the next
lower layer.
OSI
P
See Open Systems Interconnection.
packet (X.25)
A packet is a layer 3 block of information. Data is transmitted from DTE to DTE in
packets. Packets are transmitted through a network using the information field of
layer 2 frames. Different types of packets are concerned with call set-up, flow and
error control, and transmission of data. The data field of a layer 3 packet is used to
communicate higher layer data and control information.
packet assembler/disassembler (PAD)
A service that converts asynchronous terminal data to X.25 packets and vice versa. It
enables an asynchronous terminal to access computers connected to a PDN. The PAD
is defined in ITU/TSS X.3.
Glossary–10
7831 5470–200

Glossary
packet layer services (PLS)
A feature of PSCS that gives application software (in a Series 1100 host) access to the
X.25 services of the PSCS level 3/4 platform.
Packet Switched Communications Software (PSCS)
One of the program products from the Open Systems products available for Telcon.
PSCS enables communication between DCPs and other devices attached to packetswitched
PDNs. It also enables point-to-point connections using the Recommendation
X.25 protocol defined by the International Telecommunications
Union/Telecommunications Standardization Sector (ITU/TSS), formerly the
Consultative Committee on International Telephone and Telegraph (CCITT).
packet-switched network
A network based on packet-switching technology in which data is transmitted in units
called packets. Messages are split into packets, then routed independently on a
store-and-forward basis and reassembled at the receiving end of the communication
link. Packet-switched data transfer uses the communication link only during the time
of actual transmission.
PAD
PDN
See packet assembler/disassembler.
See public data network.
permanent virtual circuit (PVC)
A circuit connection in which a permanent association exists between two DTEs. Call
set-ups or clearing procedures are not possible or necessary.
PLS
PPN
primitive
See packet layer services.
See private packet network.
A type of command or instruction passed between software entities. A primitive
represents the function executed by a specific assembly language routine. There are
four types of primitives: request, indication, response, and confirm.
private packet network (PPN)
An X.25 network operated by a private concern, such as a corporate-wide X.25
network.
7831 5470–200 Glossary–11

Glossary
protocol
PSCS
The set of rules or conventions used to govern the interactions of processes,
applications, or components within the system.
See Packet Switched Communications Software.
public data network (PDN)
A digital data network that provides communication service for customer hosts and
terminals. Public data networks use either the X.25 packet-switched protocol or the
circuit-switched X.21 protocol. See also Packet Switched Communications Software.
PVC
R
See permanent virtual circuit.
recognized private operating agency (RPOA)
A private network recognized by another network. Calls destined for the RPOA can be
routed by the independent network.
Recommendation X.3
A ITU/TSS standard that defines operating characteristic parameters for asynchronous
terminals connected to a PAD. The standard provides 22 parameters that define
characteristics, including data echoing (half or full duplex), data forwarding, (end of
message) characters, printable characters, and editing characters. Each connected
terminal may select its own combination of parameter values.
Recommendation X.25
A ITU/TSS standard that defines the communication protocol for DTE and DCE
devices operating in the packet mode. The standard includes procedures for the
physical, link, and packet levels, which are the first three of seven layers in the
International Standards Organization's Reference Model.
Recommendation X.28
A ITU/TSS standard that defines how an asynchronous terminal and a PAD are to
communicate. The standard includes line characteristics, initialization, call
establishment, clearing, and actions taken for operation parameters defined in
Recommendation X.3.
Glossary–12
7831 5470–200

Glossary
Recommendation X.29
A ITU/TSS standard that defines procedures for the exchange of control information
and user data between a PAD and a DTE. The standard defines control messages
which allow a DTE to set and/or read the X.3 parameter settings for a specific
terminal actively connected to the PAD.
Recommendation X.75
A ITU/TSS standard that defines the communication protocol between two PDNs. The
standard is in most cases identical to Recommendation X.25, but includes special
considerations unique to internetworking between two packet networks.
route control (RTC) protocol
A protocol that determines the transport network route or path over which particular
network data units (NDUs) travel to reach the paired data unit control (DUC) entity.
RTC applies one of a selection of routing algorithms according to the needs of the
transport network.
RPOA
RTC
S
SNA
SNA/net
SVC
See recognized private operating agency.
See route control protocol.
See Systems Network Architecture.
A Unisys implementation of Systems Network Architecture (SNA) on the DCP family
of communications processors. SNA/net is based on the concepts of extending SNA
networks to accommodate non-SNA network needs, and operating the SNA network
without continuous dependence on the host.
See switched virtual circuit.
switched virtual circuit
A circuit connection in which a call set-up procedure and a call clearing procedure
will determine a period of communication between two DTEs. All data are delivered
from the network in the same order in which they are received by the network.
7831 5470–200 Glossary–13

Glossary
synchronous transmission
The transmission of data at a fixed rate with the transmitter and receiver
synchronized. This eliminates the need for start-stop elements.
Systems Network Architecture (SNA)
A data communication and networking architecture designed by IBM. SNA totally
describes the logical structure, formats, protocols, and operational sequences for
transmitting information units through a communication system. The structure of SNA
enables the ultimate origins and destinations of information (the end users) to be
independent of, and unaffected by, the specific communication system services and
facilities used for information exchange.
T
TCP/IP
Telcon
See transmission control protocol/internet protocol.
A Unisys distributed communications software system for data communication
networks. The software runs in a Distributed Communications Processor (DCP) and is
defined by the Distributed Communications Architecture (DCA). Telcon software
handles communication connections to CMS 1100, to Telcon software in other DCPs,
to various terminal types, and to other DCA compliant entities.
transmission control protocol/internet protocol (TCP/IP)
A set of protocols developed by the Department of Defense (DOD) to connect
different kinds of networks and computers. The most common implementation of
TCP/IP is UNIX systems, which use TCP/IP protocols to communicate over an IEEE
LAN. Some UNIX vendors integrate TCP/IP communication software into operating
system software. TCP/IP protocols are based on a four-layer architecture model, as
opposed to the OSI seven-layer model. The four layers in the TCP/IP model are:
process/application (layer 4), host-to-host (layer 3), internet (layer 2), and network
access (layer 1). The main differences between the TCP/IP model and the OSI model
are the location of reliability control (error detection and recovery) within the
protocol hierarchy and the application system structure defined by each model. TCP/IP
is required for the Defense Data Network (DDN).
trunk
Glossary–14
A collection of one or more physical data links (or lines) that connect DCPs. Trunk
lines are full-duplex. The physical lines are operated in parallel to improve reliability
and performance and reduce costs.
7831 5470–200

U
U Series
The family of U 6000 hardware products.
U.S. GOSIP
See Government Open Systems Interconnection Profile.
Glossary
UTS 4000
The family of interactive general-purpose display terminals that includes the UTS 10
teletypewriter (TTY) terminal, the UTS 20 editing terminal, the UTS 30 editing
terminal, the UTS 40 programmable terminal, the UTS 4000 cluster controller, and the
UTS 4040 cluster controller.
V
Videotex 1100
A software package that connects standard public Videotex terminals or personal
computers with appropriate software decoders to an OS 1100 host computer through a
Telcon network. A Videotex gateway allows these connections through a
packet-switched PDN. Videotex 1100 supports the protocols defined by Prestel, CEPT,
Teletel, and NAPLPS.
virtual circuit
A path through the network over which X.25 data packets and control packets are
exchanged. A virtual circuit is identified by logical channel numbers at each end of the
connection. Synonymous with network connection. A two way logical connection
through a network, which provides error handling, DTE-to-DTE flow control, routing,
and packet sequencing. The routing taken by data on a virtual circuit is not hard
wired, but is implemented by the network when the call is established. See also
permanent virtual circuit, switched virtual circuit.
W
wide area network (WAN)
A computer network that can spread over large geographic areas. It can connect
cities, countries, and continents.
WAN
See wide area network.
7831 5470–200 Glossary–15

Glossary
X
X.3
X.21
X.21 bis
X.25
See Recommendation X.3.
The ITU/TSS Recommendation that defines a protocol for communication between
user devices and a circuit-switched network.
The ITU/TSS Recommendation (a modification of X.21) that enables existing data
terminals to access a digital network over telephone lines.
See Recommendation X.25.
X.25 PDN
See X.25 public data network.
X.25 PSCS
See Packet Switched Communications Software.
X.25 public data network (X.25 PDN)
A communication network system that offers users the worldwide capabilities of
international standard X.25, a fully certified, error-free public data network system.
X.28
X.29
X.75
Glossary–16
See Recommendation X.28.
See Recommendation X.29.
See Recommendation X.75.
7831 5470–200

Index
A
Accunet, 1–7, 6–27, 6–63 to 6–64
activating
X.25 facilities, 5–29
adding
nodes and DTEs to a DCE Network, 3–13
AIR/net, 6–17
Arpac, 1–7, 6–27, 6–63 to 6–64
Austpac, 1–7, 6–27, 6–63 to 6–64
authorization levels
for NMS commands, 5–3
B
BX.25, 1–7, 6–27, 6–63 to 6–64
C
call packets
rerouting, 5–19
call routing, B–1
CALLED option
configuration, 2–37
CALLING option
configuration, 2–37
capacity limitations, 1–11
certifications, 1–7
closed user group (CUG)
configuration procedure, 3–28
CLSTR statement, 6–4
CNMS interface, 1–5
coded character set, 1–10, 6–58
configuration example
DCE Network, 4–48
IS-PC, 4–24
mixed trunk, 4–14
multilink trunk, 4–8
packet layer services (PLS), 4–43
PDN trunk, 4–3
U Series, 4–24
UTS 4000 Cluster Controller, 4–19
X.28/PAD, 4–29
X.29 PAD with configured DTEs, 4–38
X.29 PAD with nonconfigured DTEs,
4–33
configuring basic connections to networks,
2–3
configuring CALLED options, 2–37
configuring CALLING options, 2–37
configuring CUGs, 3–27
configuring DCE Networks, 3–1
procedure, 3–10
configuring DCPs as DTEs
example, 2–13
illustration, 2–10
procedure, 2–11
configuring DDN connections
example, 2–6
illustration, 2–5
procedure, 2–6
configuring DTE hunt groups
DCE Network, 3–33
example, 3–34
illustration, 3–34
procedure, 3–33
configuring DTE subaddresses
example, 3–35
illustration, 3–36
procedure, 3–35
configuring DTEs with PVCs
example, 2–26
illustration, 2–25
procedure, 2–26
configuring DTEs with SNA protocols
example, 2–24
illustration, 2–23
procedure, 2–24
configuring flow control negotiation
example, 3–32
procedure, 3–32
7831 5470–200 Index–1

Index
configuring frame level windows, 2–35
configuring frame size, 2–34
configuring ILM-20 connections to a DTE
example, 3–37
procedure, 3–37
configuring incoming call routing
precedence, 2–41
configuring internal DTEs
example, 3–18
illustration, 3–16
procedure, 3–17
configuring internal DTEs for U Series or
IS-PC DTEs
example, 3–22
illustration, 3–20
procedure, 3–21
configuring multilink connections
example, 2–8
illustration, 2–7
procedure, 2–7
configuring multilink connections (DCE)
example, 3–39
illustration, 3–39
procedure, 3–38
configuring one-node DCE Networks
example, 3–12
illustration, 3–10
procedure, 3–11
configuring packet layer services (PLS)
(See configuring PLS interfaces as DTEs)
configuring packet level window size, 2–33
configuring packet size, 2–33
configuring partial DTE addresses, 2–38
for incoming calls, 2–38
for outgoing calls, 2–38
for outgoing/incoming calls, 2–39
configuring PDN connections
example, 2–5
illustration, 2–3
procedure, 2–4
configuring permanent virtual circuits, 2–36
configuring PLS interfaces as DTEs
example, 2–18
illustration, 2–17
procedure, 2–18
configuring priority virtual circuits
example, 3–30
procedure, 3–30
configuring reverse charging
example, 3–31
procedure, 3–31
Index–2
configuring routing information, B–2
configuring special DCE Network
capabilities, 3–27
configuring standard capabilities, 2–1
configuring U Series or IS-PC as DTEs
example, 2–22
illustration, 2–21
procedure, 2–22
configuring U Series running DNS as a DTE
example, 2–20
illustration, 2–19
procedure, 2–20
configuring UTS 4000 Cluster Controllers as
DTEs
example, 2–16
illustration, 2–14
procedure, 2–15
configuring X.28/PADs
example, 2–31
illustration, 2–29
procedure, 2–30
configuring X.29 PADs
example, 2–28
illustration, 2–27
procedure, 2–28
configuring X.75 interfaces
example, 3–26
illustration, 3–24
procedure, 3–25
connectionless-oriented service, 6–16
controlling
DCE Network statistics, 5–9
CORP/net, 6–17
creating
network addresses, 3–5
CUG
(See closed user group)
D
D-bit implementation
feature description, 1–9
data network identifier code (DNIC), 3–5,
3–7
data terminal equipment
defining, 6–5
7831 5470–200

Datapac, 1–7, 6–27, 6–63 to 6–64
Datex, 1–7, 6–27, 6–63 to 6–64
Datex-P, 1–7, 6–27, 6–63 to 6–64
DCA support
feature description, 1–7
DCE Network
capabilities, 1–3
configuration example, 4–48
limitations, 1–13
DCE Network configuration
adding nodes and DTEs, 3–13
basic network, 3–10
closed user group, 3–27
creating network addresses, 3–5
DNIC, 3–7
drawing a network map, 3–3
DTE hunt groups, 3–33
DTE identifier, 3–5
flow control negotiation, 3–32
ILM-20 connection, 3–37
internal DTE for U Series or IS-PC, 3–20
internal DTE, 3–16
multilink connection, 3–38
node number, 3–7
one-node network, 3–10
planning, 3–3
priority virtual circuits, 3–30
reverse charging, 3–31
selecting statements, 3–8
special capabilities, 3–27
two-node network, 3–13
X.75 interface, 3–24
DCE Network routes
defining, 6–73
DCE Network statistics
controlling statistics gathering, 5–9
DCE Network with an X.75 interface
example, 3–26
illustration, 3–24
procedure, 3–25
DCP
as configured DTEs, 2–9 to 2–11
connection to DDN, 2–5
DCS, 1–7, 6–27, 6–63 to 6–64
DDN, 6–27, 6–63 to 6–64
certification, 1–7
configuration, 2–6
connection to DCP, 2–5
Index
DDX, 1–7
deactivating
X.25 facilities, 5–4
Defense Data Network, 1–7, 6–27, 6–63 to
6–64
defining
data terminal equipment, 6–5
DCE Network routes, 6–73
DTE communication attributes, 6–15
DTEs, 2–9
line characteristics, 6–34
network characteristics, 6–61
network connection, 6–38
PAD operational parameters, 6–50
physical communications lines, 6–36
routing precedence, 6–75
terminal, 6–58
UTS terminal clusters, 6–4
X.25 PSCS end users, 6–25
displaying
line activity, 5–6
status of lines, 5–11
DN1, 1–7, 6–27, 6–63 to 6–64
DNIC
(See data network identifier code)
DOWN command, 5–4
DTE
DCP as a DTE, 2–10
defining systems as DTEs, 2–9
hunt group configuration, 3–33
minimizing number of PLS DTEs, 1–9
PLS interface as a DTE, 2–17
running SNA protocols, 2–23
U Series as a DTE, 2–19
U Series or IS-PC as a DTE, 2–21
UTS 4000 Cluster Controller as a DTE,
2–14
with PVCs, 2–25
DTE communication attributes
defining, 6–15
DTE hunt group configuration, 3–33
DTE identifier, 3–7
DTE routing
routing precedence, 1–9
DTE statement, 6–5
DTEs on DCE Networks, 6–11
DTEs on PDNs or private networks, 6–6
outgoing call routing, B–1
use as filter for incoming calls, 1–16
use in DCE Network configuration, 3–8
7831 5470–200 Index–3

Index
DTE subaddress
configuration, 3–35
DTETYPE statement, 6–15
DCE Networks, 6–23
standard packet network, 6–16
use in DCE Network configuration, 3–8
dynamic line switching, 1–10
E
end users
defining for X.25 PSCS, 6–25
EU statement, 6–25
DCE Network, 6–32
PLS end users, 6–30
use in DCE Network configuration, 3–8
X.28/PAD end users, 6–25
Euronet, 6–27, 6–63 to 6–64
European CTS/WAN certification, 1–7
European NET2 certification, 1–7
F
fast select
feature description, 1–8
FIPS conformance tests, 1–7
flow control negotiation
configuration, 3–32
feature description, 1–8
frame size, 1–8
configuration, 2–34
H
hardware/DCP system resources
troubleshooting, 7–6
hunt groups
configuration, 3–33
Index–4
I
Iberpac, 1–7, 6–27, 6–63 to 6–64
idle trunk circuit handling
configuration, 2–10 to 2–11, 2–19 to 2–20
feature description, 1–5
ILM-20
support feature, 1–4
initialization
troubleshooting, 7–5
installation verification, 7–4
internal DTE
configuration, 3–16
for U Series or IS-PC DTEs, 3–20
internationalization, 1–10
IS-PC
configuration example, 4–24
Itapac, 1–7, 6–27, 6–63 to 6–64
ITU/TSS (CCITT) compliance
1988 CCITT compliance, 1–10
L
layer 3/4 platform
feature description, 1–5
layer 4 connection verification, 7–11
LCLASS statement, 6–34
ILM-20 lines, 6–35
standard communications lines, 6–34
Level4 program definition for SNA/net, 1–17
limitations
DCE Network, 1–13
X.25 PSCS, 1–11
line activity
displaying, 5–6
line characteristics
defining, 6–34
line failure
general, 7–3
specific, 7–8
line operation verification, 7–3
LINE statement, 6–36
LIST command, 5–6
7831 5470–200

M
M-bit implementation
feature description, 1–9
message data transfer performance
verification, 7–15
message tracing, 1–10, 5–21, 7–14
Mexpac, 1–7, 6–27, 6–63 to 6–64
migration issues, 1–15
mixed trunk
configuration example, 4–14
multilink
configuration, 3–38
connection configuration, 2–7
feature description, 1–8
trunk configuration example, 4–8
N
NET2 certification, 1–7
NETID values, 6–64
network addresses, 3–5, 3–7
network certifications, 1–7
network characteristics
defining, 6–61
network connections
basic configurations, 2–3
defining, 6–38
Network Load Utility
(See NLU) 1–14
Network Management Services (NMS)
(See NMS commands)
network support
by X.25 PSCS, 6–27
networks
supported by X.25 PSCS, 1–7
NLU, 1–14
NMS commands
command authority, 5–3
DOWN, 5–4
enhancements, 5–1
LIST, 5–6
RECORD, 5–9
SNAP=DCEF trace files, C–4
SNAP=X25 trace files, C–2
STAT, 5–11
SWITCH, 5–19
TRAC, 5–21
UP, 5–29
node
adding to DCE Network, 3–13
number, 3–7
NOPN, 1–7, 6–27, 6–63 to 6–64
NPDN, 1–7, 6–27, 6–63 to 6–64
O
one-way logical channels
feature description, 1–8
operational parameters for a PAD
defining, 6–50
OSI support
feature description, 1–6
OSI systems
as configured DTEs, 2–9
outgoing call routing, B–1
P
Index
packet layer services (PLS)
configuration example, 4–43
configured as a DTE, 2–17
feature description, 1–5, 1–9
packet size
configuration, 2–33
feature description, 1–8
PAD operational parameters
defining, 6–50
partial DTE addresses
configuration, 2–38
PDN
connection to X.25 PSCS, 2–3
supported types, 1–7
PDN trunk
configuration example, 4–3
PDNGRP statement, 6–38
DCE Networks, 6–47
DDN, 6–43
PDNs and private packet networks, 6–39
use in DCE Network configuration, 3–8
PDNPAD statement, 6–50
permanent virtual circuits (PVCs)
configuration, 2–25, 2–36
DTE configuration, 2–25
feature description, 1–8
7831 5470–200 Index–5

Index
physical communications lines
defining, 6–36
priority virtual circuits
configuration, 3–30
feature description, 1–8
product
limitations, 1–11
overview, 1–3
restrictions, 1–12
protocols
supported, 1–6
PSCS
capacity limitations, 1–11
limitations, 1–11
restrictions, 1–12
PSCSNET, 6–27, 6–63 to 6–64
PSS, 1–7, 6–27, 6–63 to 6–64
public data networks
(See PDN)
R
recognized private operating agencies
(See RPOA)
RECORD command, 5–9
Renpac, 1–7, 6–27, 6–63 to 6–64
rerouting
call packets, 5–19
reserved words, A–1
resiliency, 1–10
restrictions, 1–12
reverse charging
configuration, 3–31
feature description, 1–9
routing
calls, B–1
non-configured incoming calls, 1–15
routing precedence
specifying, 6–75
RPOA
feature description, 1–8
S
selecting
DCE Network statements, 3–8
SITA, 1–7, 6–27, 6–63 to 6–64
Index–6
SNA support
feature description, 1–7
SNA systems
as configured DTEs, 2–9, 2–23 to 2–24
configuration procedure, 2–24
SNAP=DCEF parameter
option format, C–4
trace entry example, C–5
SNAP=X25 parameter
option format, C–2
trace entry example, C–3
specifying
routing precedence, 6–75
STAT command, 5–11
STAT LINE command, 5–13
STAT PDTE command, 5–15
STAT PTRK command, 5–17
status of lines
displaying, 5–11
supported
networks, 1–7, 6–27
protocols, 1–6
SWITCH command, 5–19
T
TCP/IP support
feature description, 1–5
TCP/IP systems
as configured DTEs, 2–9
Telenet, 1–7, 6–27, 6–63 to 6–64
Telepac, 1–7, 6–27, 6–63 to 6–64
Telepacp, 1–7, 6–27, 6–63 to 6–64
TERM statement, 6–58
terminals using the UTS 4000 Cluster
Controller, 6–58
terminals using the X.29 PAD, 6–59
terminal
defining, 6–58
throughput class assignment,
facility codes, 6–20
throughput class negotiation
feature description, 1–9
TRAC command, 5–21, 7–14
trace file formats, C–1, C–4
TRAC SNAP DCEF command, 5–27
TRAC SNAP X25 command, 5–21
trace entry example
SNAP=DCEF, C–5
SNAP=X25, C–3
7831 5470–200

tracing
messages, 5–21
transit delay
feature description, 1–9
Transpac, 1–7, 6–27, 6–63 to 6–64
troubleshooting
connections, 7–13
DCP/OS resources, 7–17
external facilities, 7–15
facility constraints, 7–19
hardware/DCP system resources, 7–6
incompatible flow control values, 7–18
incompatible frame control values, 7–19
initialization, 7–5
installation, 7–4
layer 3/4 platform interface user reports,
7–14
layer 4 connection verification, 7–11
line characteristics, 7–20
line failure (general), 7–3
line failure (specific), 7–8
link level characteristics, 7–19
message data transfer performance
verification, 7–15
message tracing, 7–14
NMS command verification, 7–11
packet level characteristics, 7–18
subscription parameters, 7–20
Telcon CENLOG reports, 7–13
Telcon or host interface resources, 7–16
TRAC command, 7–14, 7–16, 7–19
virtual circuit connection, 7–11, 7–15
X.25 line monitor, 7–16, 7–19
trunk configuration, 2–10 to 2–11, 2–19 to
2–20
U
U Series
configuration example, 4–24
U Series systems
as configured DTEs, 2–9, 2–19 to 2–22
communications with, 1–5
U.S. GOSIP certification, 1–7
UP command, 5–29
Index
UTS 4000 Cluster Controller
as configured DTEs, 2–9, 2–14 to 2–15
communications with, 1–5
configuration example, 4–19
UTS terminal clusters
defining, 6–4
V
verification
connections (layer 4 or service
operation), 7–11
connections (NMS commands), 7–11
installation, 7–4
line operation, 7–3
message data transfer performance, 7–15
virtual circuit connection, 7–11
Videotex, 1–15, 2–9, 2–28, 2–42 to 2–43,
3–17, 6–17, 6–76
virtual circuit connection
verification, 7–11
W
window size
configuring frame level windows, 2–35
configuring packet level window size,
2–33
feature description, 1–8
X
X.25 facilities
activating, 5–29
deactivating, 5–4
X.25 implementation
capacity limitations, 1–11
feature description, 1–5
restrictions, 1–12
special capabilities, 1–8
X.25 PSCS end users
defining, 6–25
X.25 PSCS reserved words, A–1
X.28 implementation
feature description, 1–5
7831 5470–200 Index–7

Index
X.28/PAD
configuration example, 4–29
configuration, 2–29
X.29 implementation
feature description, 1–5
X.29 PAD
configuration, 2–27
X.29 PAD with configured DTEs
configuration example, 4–38
X.29 PAD with nonconfigured DTEs
configuration example, 4–33
X.3 implementation
feature description, 1–5
X.75 interface
configuration, 3–24
X25DEF statement, 6–61
supported networks, 6–63
use in DCE Network configuration, 3–8
X25NET statement, 6–73
use in DCE Network configuration, 3–8
X25ROUTE statement, 1–15 to 1–16, 2–41,
6–75
Index–8
7831 5470–200