Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

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Wireless Local Area Networks (WLANs)
Traffic Management (QoS)
• By default, high-priority queues on the RP use an AIFSN value of 1 ms;
high-priority queues on stations use an AIFSN value of 2 ms. You
might want to reserve the 1-ms AIFSN for RPs.
• When you grant a queue a Transmit Ops, you allow a station that wins
access to the radio continued access to the medium for that length of
time. If you set this value excessively high, then lower-priority traffic,
and even other high-priority traffic, may be unacceptably delayed.
Although the Web browser interface lists the maximum value as
65,535, generally the Transmit Ops is set in terms of tens, or at the
most, hundreds of milliseconds—not thousands. In several seconds,
applications can time out, frustrating users throughout your network.
• In a network with many users and high congestion, increasing CW
Maximum values can decrease the number of collisions.
• The CW Maximum value must always be higher than the CW Minimum
value.
Viewing and Customizing RP WMM Parameters
As discussed earlier, RPs handle traffic as dictated by the WMM parameters
(AISFN and so forth) for the traffic’s AC. Also as discussed earlier, the Wireless
Edge Services xl Module assigns traffic to an AC according to the WLAN
setting or, if the AC is set to automatic/WMM, according to priority value.
The ProCurve 210, 220, and 230 RPs use default parameters that work for
nearly all applications. (For example, the parameters are such that voice
frames more quickly and more often win access to the medium.)
Note Because the Wireless Edge Services xl Module automatically defines settings
such that traffic in a higher-priority queue receives lower latency, the default
radio WMM settings are usually adequate. Incorrect settings can adversely
affect network performance; ProCurve Networking strongly recommends
that you do not change these parameters.
Like other radio settings, you can alter:
■ the WMM queue parameters that the Wireless Edge Services xl Module
sends to newly adopted radios
■ the WMM queue parameters used by particular radios