WESM zl Management and Configuration Guide WT.01.28 and greater

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Radio Port Configuration
Quality of Service (QoS) on RP Radios
For more precise prioritization, you can enable Wi-Fi Multimedia (WMM) on a
WLAN.
WMM
WMM, which is Wi-Fi’s implementation of a portion of the IEEE 802.11e-2005
ratified specification for wireless QoS enhancements, includes packet prioritization,
scheduled access, and call admission control. WMM divides traffic into four access
categories (ACs): voice, video, best effort, and background and allows RPs to queue
outbound wireless traffic according to each AC.
The RP creates one queue for each AC on each of its radios, using an 802.1p value
(by default) or Differentiated Service Code Point (DSCP) to assign a particular frame
to a queue. The RP radio then transmits traffic in the queue according to the RP WMM
parameters for that AC.
Table 3-4 shows the WMM queues on the ProCurve RPs 210, 220, and 230. Each
radio on an RP has four queues for outbound wireless traffic. These queues and all
radio WMM settings apply to traffic from the RP to wireless stations.
Table 3-4. WMM Priority Queues
Each outbound radio queue is defined by different WMM parameters, which deter-
mine how the RP contends for the medium in order to transmit frames in that queue.
These parameters include:
■ the arbitration IFS number (AIFSN)—the time that the medium must be conten-
tion free before the RP can attempt to transmit a frame (first decrementing a
random backoff time)
■ the minimum contention window (CW Min)—the maximum value for the initial
random backoff time
■ the maximum contention window (CW Max)—the maximum value for the
random backoff time for a frame that has collided
■ the transmit opportunity (Transmit Ops)—the continuous time during which a
device that has won control of the radio can retain control
Queue Number AC
1 Background
2 Best effort
3 Video
4 Voice