CCNA Voice Portable Command Guide 1587204428_ch01.pdf

CHAPTER 1
Voice Fundamentals for Unified
Communication
This chapter provides information on the following topics:
■ Voice Fundamentals
■ Cisco VoIP Structure
■ Common Topologies
■ Traditional Voice Network
■ Traditional Data Network
■ Today’s Converged Network
Voice Fundamentals
Over the past decade, as IP-based protocols have matured, a trend has occurred. The
trend has been moving away from traditional PBX-based telephony systems and moving
toward implementing a converged data and voice IP-based network. This has enabled
a lower-cost solution to be deployed over the existing infrastructure that exists for the
network.
Whether you have a background in traditional voice, networking, or are new to this
field altogether, there are a lot of terms and concepts to learn. The goal for this portable
command guide is to help you quickly dive into what you need or want to know to help
implement a VoIP solution at work, to help you advance your knowledge to attain the
CCNA Voice certification, or simply to further your knowledge in a technology that
is foreign to you. Table 1-1 lists commonly used acronyms and concepts with a brief
description of each. These terms and concepts are used throughout this portable command
guide.

2 Voice Fundamentals
Table 1-1 Voice Fundamentals – Concepts and Acronyms
Acronym/Concept Description
802.1Q IEEE Standard specifying a trunking protocol that tags
frames with the VLAN number they are sourcing from
Analog Signal Signaling method used to measure change in a continuous
nature
ANI
Automatic Number Identifi cation
CAS
Channel Associated Signaling
CCS
Common Channel Signaling
CDP
Cisco Discovery Protocol
CLI
Command Line Interface
CME
Cisco Unifi ed Communications Manager Express
Codec Encoding/Decoding mechanism for compressing voice
across a data network. The term’s original meaning is
coder/decoder.
CUC
Cisco Unity Connection
CUCM or CM
Cisco Unifi ed Communications Manager (previously
known as Call Manager (CM)
CUP
Cisco Unifi ed Presence
E.164
PSTN International number plan
Digital Signal A string of bits (1s or 0s).
E&M (Ear and Mouth) or (Earth and Magnet)
FXO
Foreign Exchange Offi ce
FXS
Foreign Exchange Station
NANP
North American Numbering Plan
NTP
Network Time Protocol
PBX
Private Branch Exchange
PoE
Power over Ethernet
PSTN
Public Switched Telephone Network
RBS
Robbed Bit Signaling
RTCP
Real-Time Transport Control Protocol
RTP
Real-Time Transport Protocol
SCCP
Skinny Client Control Protocol
SIP
Session Initiation Protocol
SRST
Survivable Remote Site Telephony
TDM Time Division Multiplexing is the process of transmitting
multiple channels of voice or data in specifi c time
slots over a single digital connection.

Cisco VoIP Structure
Common Topologies 3
It is beneficial to know what products exist in the Cisco world for voice. Depending
upon the size of the organization, numerous solutions are available:
■ Cisco Unified Communications Manager: This solution is the pinnacle of the
Cisco Voice solution. Cisco Unified Communications Manager provides all the
functionality you would want or need within an enterprise-class voice solution.
This is the ideal solution for a large organization that requires the complexity,
yet granularity, of having an enterprise voice system. You can add voicemail
functionality to this system when implementing Cisco Unity Connection (CUC).
You can also add presence features that will be discussed later within this portable
command guide. The presence functionality is known as Cisco Unified Presence
(CUP). This is an extremely flexible and scalable solution.
■ Cisco Unified Communications Manager Express: This solution is for the
small- to medium-size business that does not require the complexity, nor the
extensive scalability that Cisco Unified Communications Manager has to offer. It
is an ideal solution for a small- to medium-size business that would like a subset
of the features that CUCM offers. This can also be used for a remote office solution
with CUCM utilizing SRST.
■ Cisco Unified Communications Manager—Business edition: Cisco developed
this solution for an organization that wants the full-blown implementation of
CUCM; however, the organization will never grow beyond 1,000 users (Note: At
the time of this writing, three business editions are available. This is a great solution
at a great price point for the small- to medium-size organization.
■ Cisco Unified Communications 500 Series for Small Business (UC500): Cisco
developed this solution for the small business market that just needs a quick, easy
to set up and configure platform to get its organization up and running on a VoIP
solution. This system scales up to 138 users. This is truly meant for the small
business market.
Common Topologies
This section describes common topologies that you find in the industry and in textbooks
when studying voice technologies and bridging the gap between data and voice networks.
Figure 1-1 represents the traditional voice network for a traditional PBX connected to
the PSTN via a copper ground start trunk or loop start trunk. This also shows traditional
phones as terminals and a traditional fax machine, in addition to a connection to the
voicemail system.

4 Common Topologies
Figure 1-1 Traditional Voice Network
PBX
PSTN
IP IP IP
Phones
Trunk
Fax Voice Mail
Figure 1-2 represents the traditional data network that shows two locations, each with a
router, switch, and two PCs connected via a WAN connection.
Switch
Router
PCs
Figure 1-2 Traditional Data Network
WAN
Switch
Router
PCs

Common Topologies 5
Figure 1-3 represents today’s Voice over IP network that takes the best of both the
traditional voice network and the data network and combines them together in one network.
The PBX is now a server on the data network, and the traditional phones are now
IP-based. Keep in mind, you still need to maintain a connection to the PSTN for external
calls.
PoE
Switch
Voice
V
PSTN
CME
V
PoE
Switch
IP Phone
w/Station
IP WAN
IP IP
IP
Servers
PC PC
CUCM CUC CUP
Virtual or Physical
Figure 1-3 Today’s Voice over IP Network (Sometimes Referred to as a Converged
Network)