Huawei AR1200 Series - Page 51

ECWmax ECWmin AIFSN TXOPLimit
AC_VO 3 2 2 47
AC_VI 4 3 2 94
AC_BE 10 4 3 0
AC_BK 10 4 7 0
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AP EDCA parameters:
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ECWmax ECWmin AIFSN TXOPLimit Ack-Policy
AC_VO 3 2 1 47 normal
AC_VI 4 3 1 94 normal
AC_BE 6 4 3 0 normal
AC_BK 10 4 7 0 normal
---------------------------------------------------
NOTE
A STA communicates with an AP by sending radio signals over a channel. Four queues are provided for
radio packets. Packets in different queues have different opportunities to obtain transmission channels so
that differentiated services can be provided for radio packets.
The queues are AC_VO (voice queue), AC_VI (video queue), AC_BE (best effort queue), and AC_BK
(background queue) in descending order of priority.
You can change the priorities of the queues by modifying the Enhanced Distributed Channel Access
(EDCA) parameters, including the AIFSN, ECWmin, ECWmax, TXOPLimit, and ACK policy:
l AIFSN: determines the channel idle time. A greater AIFSN value indicates a longer channel idle time.
Different AIFSNs can be configured for ACs.
l ECWmin and ECWmax: ECWmin specifies the minimum backoff time, and ECWmax specifies the
maximum backoff time. They determine the average backoff time. A larger value indicates a longer
average backoff time.
l TXOPLimit: determines the maximum duration in which a STA can occupy a channel. A larger value
indicates a longer duration. If this parameter is set to 0, a STA can send only one packet every time it
occupies a channel.
l ACK policy: determines whether the packet receiver acknowledges received packets. Two policies are
available: normal ACK and no ACK.
Before occupying a channel to send packets, STAs monitor the channel. If the channel idle time is longer
than or equal to the AIFSN, each STA selects a random backoff time between ECWmin and ECWmax.
The STA whose backoff timer expires the first occupies the channel and starts to send packets over the
channel.
Step 4 (Optional) Run:
wmm edca client { ac-vo | ac-vi | ac-be | ac-bk } { aifsn aifsn-value | ecw ecwmin
ecwmin-value ecwmax ecwmax-value | txoplimit txoplimit-value }
*
The EDCA parameters are configured for the four WMM queues of a STA.
Step 5 (Optional) Run:
wmm edca ap { ac-vo | ac-vi | ac-be | ac-bk } { aifsn aifsn-value | ecw ecwmin
ecwmin-value ecwmax ecwmax-value | txoplimit txoplimit-value | ack-policy { normal
| noack } }
*
The EDCA parameters are configured for the four WMM queues of an AP.
----End
Checking the Configuration
Run the display wmm-profile { all | id profile-id | name profile-name } command to view the
configuration of a WMM profile.
Huawei AR1200 Series Enterprise Routers
Configuration Guide - WLAN 3 WLAN QoS Configuration
Issue 03 (2012-01-06) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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