HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual page 359

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Marking Traffic Destined to a UDP Protocol Port. It can be important
to prioritize traffic to specific, well-known UDP ports. For example, you do
not want user traffic to starve out customers accessing your business's Web
server. You can mark traffic from the server destined to the HTTP port with a
higher QoS value.
Also, VoIP and other real-time traffic requires special handling. Congestion
affects this traffic far more negatively than it does bursty data traffic. If your
VoIP applications do not themselves mark traffic with a ToS value, you should
configure the router to do so. Your service provider will inform you what type
of service you can request with various ToS values.
You should note the UDP ports on which your VoIP applications operate. You
can then match a QoS map entry to these ports.
You use this command to mark RTP packets destined to a range of UDP
destination ports:
Syntax: match ip rtp <first port number> <last port number> [all]
For example, many VoIP applications operate between ports 16,384 and
32,764. You would enter:
ProCurve(config-qos-map)# match ip rtp 16384 32764
The router matches all RTP packets destined to even port numbers in the
specified range. (Typically, servers listen for user traffic on even ports.) If you
want to match traffic to both even and odd ports, you must add the all
keyword. For example:
ProCurve(config-qos-map)# match ip rtp 16384 33764 all
You can also configure a low-latency queue on the local router interface for
VoIP traffic. This is often a better solution than relying on WFQ. WFQ only
grants high priority traffic relatively more bandwidth. It works best on rela-
tively uncongested links for which only a small percentage of the traffic has
been marked with a high priority QoS value. When many conversational
subqueues are running, the effect of a higher IP precedence is diluted. Voice
traffic may become jittery. You should place this traffic in a low-latency queue
that guarantees it a maximum absolute amount of bandwidth. For more
information on configuring bandwidth for VoIP traffic, see "Determining
Bandwidth for VoIP" on page 7-32.
Setting Up Quality of Service
Marking Packets with a ToS value
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