Datasheet

H.323 and voice services over IP
Vpacket 5100/6100 Series H.323 Telephony 3
Overview
This chapter describes the capability of the 6100 VDR to support IP telephony and the basic
procedures for supporting the voice ports using the Command Line Interface (CLI).
This chapter contains three sections:
• Background information about IP telephony based on H.323
• A description of the uses of telephony channels (TCIDs) and their coding profiles for
encoding the characteristics of traffic flow
• Procedures for entering the telephony command shell and accessing help
H.323 and voice services over IP
The basic conditions that required bringing together data and voice routing capabilities were the
development of specialized telephonic applications connecting LAN devices, across a WAN, and
with interfaces to the PSTN. These required attention to several key areas:
• Operational differences between packet-switched and circuit-switched environments
• Major issues revolving on the management of bandwidth, QoS, and latency
These required the development of protocols capable of managing:
• Audio compression to reduce bandwidth
• Sensitivity to latency on the audio path–a 200ms round trip is considered acceptable
• Use jitter buffers and codecs that minimize the network impacts
H.323 is an “umbrella standard” that encompasses many subordinate standards and allows the
reuse of existing data and telecommunications standards such as Q.931. H.323 defines a flexible
means for multimedia teleconferencing equipment to communicate and provides application-
sharing features over an IP stack using a variety of devices including videophones, desktop PCs,
and multiport gateways.
Note. G.726 is not supported in H.323.
Setting up voice ports for H.323
To enable voice services, you must individually set up each voice port. Each voice port needs to
have telephony channel identifier (TCID) parameters configured, a set coding profile and then
any coding profile parameters need to be configured.