H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 166)

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• Users-based admission policy—If the number of clients using high-priority AC queues plus the
clients requesting high-priority AC queues is smaller than or equal to the maximum number of
high-priority AC queue clients, the request is accepted. Otherwise, the request is rejected. During
calculation, a client is counted once, even if the client is using both the AC-VO and AC-VI queues.
U-APSD power-save mechanism
U-APSD improves the 802.11 APSD power saving mechanism. When associating clients with AC queues,
you can specify how these AC queues are handled. Some AC queues can be trigger-enabled, and some
AC queues delivery-enabled. You can also specify the maximum number of data packets delivered in a
trigger packet.
Both the trigger attribute and the delivery attribute can be modified when flows are established using
CAC. When a client sleeps, the delivery-enabled AC queue packets destined for the client are buffered.
The client must send a trigger-enabled AC queue packet to get the buffered packets. After the AP receives
the trigger packet, packets in the transmit queue are sent. The number of packets sent depends on the
agreement made when the client was admitted. AC queues without the delivery attribute store and
transmit packets as defined in the 802.11 protocol.
SVP
SVP can assign packets with the protocol ID 119 in the IP header to a specific AC queue. SVP stipulates
that random backoff is not performed for SVP packets. Therefore, you can set both ECWmin and
ECWmax to 0 when there are only SVP packets in an AC queue.
ACK policy
WMM defines two ACK policies: Normal ACK and No ACK.
• When the no acknowledgement (No ACK) policy is used, the recipient does not acknowledge
received packets during wireless packet exchange. This policy is suitable in an environment where
communication quality is fine and interference is weak. While the No ACK policy helps improve
transmission efficiency, it can cause increased packet loss when communication quality deteriorates.
This situation results from no re-transmission of packets that are not received.
• When the Normal ACK policy is used, the recipient acknowledges each received unicast packet.
Protocols and standards
• 802.11e-2005, Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,
IEEE Computer Society, 2005
• Wi-Fi, WMM Specification version 1.1, Wi-Fi Alliance, 2005
Configuring WMM
Step Command Remarks
1. Enter system view. system-view N/A
2. Create a radio policy and
enter radio policy view. wlan radio-policy
radio-policy-name
N/A