Administration of the Avaya G350 Media Gateway - Avaya Support

Configuring VoIP QoSConfiguring RTP and RTCPVoIP 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 a12-byte header on top of other (IP, UDP) headers. Running on PPP or frame relay, theseprotocols can be compressed.Use the ip rtp port-range command to configure the range of UDP ports for RTP.Note:Note:This range should match the range configured in the IP_network region to whichthe G350 is assigned in the ACM.Configuring RTP header compressionUse RTP header compression to reduce the amount of bandwidth needed for voice data. TheG350 RTP Header Compression process is based on the following:●●The packet order on a PPP and Frame Relay link is preserved.After transmitting full headers, usually only the deltas from the full packet’s header need tobe sent, and not the full header itself. This is due to the IP, UDP, and RTP header structure.● Since the deltas are often constant, the second order delta is 0 and does not need to betransmitted.You can configure how often the full header is transmitted, either as a function of time ortransmitted compressed packets.RTP Header Compression can reduce the size of all three headers (IP+UDP+RTP~40 bytes) to2-4 bytes.The G350 can only compress RTP packets. Any UDP packet with an even destination portwithin a user-configurable range of ports, is considered an RTP packet.The G350 can decompress any type of compressed packets. Decompression is enabledwhenever RTP compression is enabled.Use the following commands to configure RTP header compression:● Use the clear ip rtp header-compression command to clear RTP headercompression statistics either for all enabled interfaces or for a specific interface. To clearRTP compression statistics for all enabled interfaces, do not enter an interface type andnumber. There is no renegotiation of parameters.●Use the ip rtp compression-connections command to control the number of RTPconnections supported on this interface. Use the no form of this command to restore thedefault. This command also sets the number of connections in the non-TCP space, not justRTP.72 Administration of the Avaya G350 Media Gateway