HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual page 350

Setting Up Quality of Service
Configuring LLQ
N o t e
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Placing Traffic Destined to a UDP Protocol Port in a Low-Latency
Queue. VoIP and other real-time traffic requires special handling. Congestion
affects this traffic far more negatively than it does bursty data traffic. One way
of classifying VoIP traffic is noting the UDP ports on which your VoIP appli-
cations operate. You can then match a QoS map entry to these ports. You can,
of course, similarly define low-latency queues for other applications.
You use the match ip rtp command to place RTP packets destined to a range
of UDP destination ports in a low-latency queue:
Syntax: match ip rtp <first port number> <last port number> [all]
For example, RTP applications generally operate between ports 16,384
and 32,767. You would enter:
ProCurve(config-qos-map)# match ip rtp 16384 32764 all
The router matches all RTP packets destined to even port numbers in the
specified range. (Typically, servers listen for traffic on even ports.) If you want
to match traffic to both even and odd ports, you must add the all keyword.
Placing Traffic to and/or from an IP Address in a Low-Latency Queue. You
can assign packets to a low-latency queue according to the source and/or
destination IP addresses in their IP headers.
You can guarantee all traffic from a network—for example, a subnet that
transmits mission-critical data—low latency. You may also want to give pack-
ets destined to a specific address a set amount of bandwidth. For example,
you can prioritize traffic to the router's Web browser interface, so that IT staff
can manage the router despite network congestion.
You place such traffic in a queue by matching the QoS map entry to an ACL.
The ACL actually selects the traffic. An extended ACL can define traffic
according to its source and destination IP address as well as a variety of fields
in the IP, TCP, or UDP header.
To place traffic with certain values in its IP header in a low-latency queue,
you must:
1. Configure an ACL.
a. Create an extended ACL.
b. Add any necessary deny entries to the ACL.
c. Add permit entries for the addresses to or from which you want to
guarantee traffic bandwidth.
2. Match the QoS map entry to the ACL.