Command Reference Guide

3Com Router 3000 Ethernet Family
Command Reference Guide
Chapter 2 Congestion Management Configuration
Commands
3Com Corporation
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Parameter
first-rtp-port-number: Specifies the first UDP port number to initiate RTP messages.
last-rtp-port-number: Specifies the last UDP port number to initiate RTP messages.
bandwidth: Bandwidth for RTP priority queue, which is part of the maximum reserved
bandwidth in Kbps.
committed-burst-size: Committed burst size, in the range 1500 to 2000000 bytes.
Description
Use the qos rtpq command to enable RTP queue feature on an interface so as to
reserve a real-time service for the RTP packets sent to some UDP destination port
ranges.
Use the undo qos rtpq command to disable the RTP queuing feature of the interface.
By default, RTP queuing feature is disabled.
This command is applied to the delay-sensitive applications, real-time voice
transmission for example. Configured with the qos rtpq command, the system will
serve the voice services first among all other services.
The parameter "bandwidth" should be set greater than the service-required bandwidth
so as to prevent conflict caused by the burst traffic. However, the bandwidth should be
no greater than 75% of the total bandwidth. If you need to configure the bandwidth to be
greater than 75% of the total bandwidth, please first change the maximum reserved
bandwidth via qos reserved-bandwidth command.
In bandwidth allocation, the bandwidth for data load, IP header, UDP header and RTP
header is allocated, except that for the Layer2 frame header. Therefore, it is obligatory
to reserve 25% of the total bandwidth.
Caution:
Except for interfaces encapsulated with X.25 or LAPB, all physical interfaces can use
RTPQ.
You can apply an RTPQ to a dialer interface successfully only when its physical
interfaces use default queuing and have adequate bandwidth.
Related command: qos reserved-bandwidth.
Example
# Enable IP RTP Priority on Serial 1/0/0. The starting port number is 16384. The
starting port number is 16383.The RTP packets in the range of 16384~32767 of the