Using Wi-Fi Multimedia Mode - Allen-Bradley Stratix 5100 User Manual

Using Wi-Fi Multimedia Mode

When you enable QoS, the access point uses Wi-Fi Multimedia (WMM) mode
by default. WMM provides these enhancements over basic QoS mode:
• The access point adds each packet's class of service to the packet's 802.11
header to be passed to the receiving station.
• Each access class has its own 802.11 sequence number. The sequence
number allows a high-priority packet to interrupt the retries of a lower-
priority packet without overflowing the duplicate checking buffer on the
receiving side.
• WPA replay detection is done per access class on the receiver. Like 802.11
sequence numbering, WPA replay detection allows high-priority packets
to interrupt lower priority retries without signalling a replay on the
receiving station.
• For access classes that are configured to allow it, transmitters that are
qualified to transmit through the normal backoff procedure are allowed to
send a set of pending packets during the configured transmit opportunity
(a specific number of microseconds). Sending a set of pending packets
improves throughput because each packet does not have to wait for a
backoff to gain access; instead, the packets can be transmitted immediately
one after the other.
• U-APSD Power Save is enabled.
The access point uses WMM enhancements in packets sent to client devices that
support WMM. The access point applies basic QoS policies to packets sent to
clients that don't support WMM.
Use the no dot11 qos mode wmm configuration interface command to disable
WMM by using CLI. To disable WMM by using the web browser interface,
unselect the check boxes for the radio interfaces on the QoS Advanced page.
Figure 113 on page 470.
Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
Configuring QoS Chapter 16
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