Specifications

CHAPTER 8
Voice and Video in a Campus Network
VoIP traffic consists of two types: voice bearer and call control signaling. Voice bearer traffic is carried over the UDP-
based Real Time Protocol (RTP). Call control uses one of several different protocols to communicate between the phone
and UCM and between the UCM and the voice gateways.
Preparing the Network for VoIP
When adding voice or video to an existing network, you should examine several things in advance to provide the high
level of availability users expect in their phone system:
n What features are needed?: Power for IP phones, security for voice calls, and Quality of Service (QoS) to control
bandwidth, delay, jitter, and packet loss.
n The physical plant: Cabling at least CAT-5.
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CCNP SWITCH 642-813 Quick Reference by Denise Donohue
FIGURE 8-1
Some Components of
a VoIP System
WAN
PSTN
Unity Server
UCM
Server
Power over
Ethernet Switch
IP Phone
User PC
Voice and WAN
Gateway
Video Conferencing
Camera
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