Configuring Rtp And Rtcp; Configuring Header Compression; Header Compression Overview - Avaya G250 Administration

Configuring VoIP QoS

Configuring RTP and RTCP

VoIP uses the RTP and RTCP protocols to transmit and receive digitally encoded voice data.
RTP and RTCP are the basis of common VoIP traffic. RTP and RTCP run over UDP and incur a
12-byte header on top of other (IP, UDP) headers. Running on PPP or frame relay, these
protocols can be compressed.
Use the ip rtp port-range command to configure the range of UDP ports for RTP.
Note:
This range should match the range configured in the IP_network region to which
Note:
the G250/G350 is assigned in the ACM.

Configuring header compression

This section provides information about configuring header compression in the G250/G350, and
contains the following topics:

Header compression overview

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Configuring RTP, TCP, and UDP header compression
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Configuring TCP header compression
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Displaying and clearing header compression statistics
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Header compression overview
Header compression reduces the size of packet headers, thus reducing the amount of
bandwidth needed for data. The header compression method is based on the fact that most of
the header fields remain constant or change in predictable ways throughout the session. Thus,
instead of constantly retransmitting the header, each side keeps a context table of the sessions
(the normal headers), and while sending and receiving packets it replaces the full-length
headers with 1 or 2 bytes CID (context-id) plus unpredictable deltas from the last packet.
The G250/G350 offers both RTP header compression for reducing the amount of bandwidth
needed for voice traffic, and TCP and UDP header compression for reducing the amount of
bandwidth needed for non-voice traffic.
For header compression purposes, any UDP packet with an even destination port within a
user-configurable range of ports, is considered an RTP packet.
118 Administration for the Avaya G250 and Avaya G350 Media Gateways