Mitel Technical Specification 22

MiNET Specification
Section B - General Concepts
1.0 General
This specification (MTS22-B) describes in general terms the functions of the MiNET protocol. Detailed
descriptions of the protocol are contained in MTS22-C.
Although the MiNET protocol is not in strict accordance with the requirements specified in the OSI
reference model, the term layer 3 will at times be used in this document.
MiNET provides the means to establish, maintain and terminate call connections between systems (eg.
PBXs) and terminals (eg. digital telephone sets, data sets, etc.). In addition, the protocol provides
configuration and maintenance capabilities from the system to terminals, as well as rate adaption
capabilities for B-channel data connections.
MiNET makes use of the services provided by a suitable data link layer (layer 2). Specifically, the data link
layer provides the following functions to layer 3:
a) establishment of data link connections;
b) error-protected transmission of data; and
c) re-establishment of data link connection (indicating loss of information).
Note-
Examples of two suitable data link layer protocols (MiLAP and MiLAP-S) can be found in MTS21.
Layer 3 makes invisible to the user how it utilizes underlying resources, such as the data link layer, to
provide its functions.
MiNET is applicable to both D-channel and B-channel communication.
1.1 Structure of MiNET
There are three categories of services provided by MiNET:
a) call control;
b) terminal configuration and maintenance; and
c) data transport.
Within the category of data transport, the following modes are supported:
a) asynchronous ASCII data at speeds of 19.2 kbit/s or less;
b) synchronous data at speeds of 19.2 kbit/s or less;
c) IBM 3270-type synchronous data (terminal to controller); and
d) bulk data transport (ie. software downloading).
Functions performed by MiNET include the following:
a) processing of primitives for communication with the data link layer entity;
b) processing of primitives for communication with upper layers, when present;
c) generation and interpretation of layer 3 messages for peer-level communication; and
d) administration of call control, data transport, and terminal configuration and
maintenance.
1.2 Interface between layer 3 and adjacent layers
When an upper layer is present, layer 3 provides its services via a layer 3 service access point (SAP).
Similarly, layer 3 receives services from the data link layer via a data link layer SAP. Refer to
Figure 1/MTS22-B. A particular service is provided to the upper layer, or received from the lower layer,
via the exchange of sequences of primitives across the SAP. Primitives represent, in an abstract way, the
logical exchange of information and control between layers, and do not specify or constrain
implementation.
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