H3C Technologies H3C WA2600 Series WLAN Access Points - Manual (Page 55)

8-4
SVP
SVP can assign packets with the protocol ID 119 in the IP header to a specific AC. 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.
ACK policy
WMM defines two ACK policies: Normal ACK and No ACK.
z When the no acknowledgement (No ACK) policy is used, the recipient does not acknowledge
received packets during wireless packet exchange. This policy is suitable 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 is
because when this policy is used, a sender does not retransmit packets that have not been
received by the recipient.
z When the Normal ACK policy is used, the recipient acknowledges each received unicast packet.
Protocols and Standards
z 802.11e-2005, Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,
IEEE Computer Society, 2005
z Wi-Fi, WMM Specification version 1.1, Wi-Fi Alliance, 2005
WMM Configuration
Configuration Prerequisites
Enable WLAN service. For more information, see WLAN Service in the WLAN Configuration Guide.
Configuring WMM
Follow these steps to configure WMM:
To do… Use the command… Remarks
Enter system view system-view —
Enter radio interface view
interface wlan-radio
radio-number
—
Enable the WMM function wmm enable
Required
Enabled by default.
Note that: the 802.11n protocol stipulates that
all 802.11n clients support WLAN QoS.
Therefore, when the radio works in 802.11an
or 802.11gn mode, you should enable WMM.
Otherwise, the associated 802.11n clients
may fail to communicate.
Set the EDCA parameters of
AC-VO or AC-VI for clients
wmm edca client { ac-vo |
ac-vi } { aifsn aifsn-value | ecw
ecwmin ecwmin-value
ecwmax ecwmax-value |
txoplimit txoplimit-value | cac }
*
Optional
By default, a client uses the default EDCA
parameters shown in
Table 8-1 .