Brocade Mobility 7131 Access Point Product Reference Guide (Supporting software release 4.4.0.0 and later) - Manual (Page 163)

Brocade Mobility 7131 Access Point Product Reference Guide 151
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9. Click Apply to save any changes to the New QoS Policy or Edit QoS Policy screen to return to the
Quality of Service Configuration screen. Navigating away from the screen without clicking Apply
results in all changes to the screens being lost.
10. Click Cancel to securely exit the New QoS Policy or Edit QoS Policy screen and return to the
Quality of Service Configuration screen.
11. Click Logout within the Quality of Service Configuration screen to securely exit the Access Point
applet. A prompt displays confirming the logout before the applet is closed.
U-APSD (WMM Power Save) Support
The access point now supports Unscheduled Automatic Power Save Delivery (U-APSD), often
referred to as WMM Power Save. U-APSD provides a periodic frame exchange between a voice
capable MU and the access point during a VoIP call, while legacy power management is still utilized
for typical data frame exchanges. The access point and its associated MU activate the new U-APSD
power save approach when a VoIP traffic stream is detected. The MU then buffers frames from the
voice traffic stream and sends a VoIP frame with an implicit "poll" request to its associated access
point. The access point responds to the poll request with buffered VoIP stream frame(s). When a
voice-enabled MU wakes up at a designated VoIP frame interval, it sends a VoIP frame with an
implicit "poll" request to its associated access point. The access point responds to the poll request
with buffered VoIP stream frame(s).
NOTE
The access point ships with the U-APSD feature disabled by default. It is automatically enabled when
WMM is enabled for a WLAN. Thus, U-APSD is only functional when WMM is enabled. If WMM is
disabled, then
U-APSD is disabled as well.
CW Min The contention window minimum value is the least amount of time the MU waits before
transmitting when there is no other data traffic on the network. The longer the interval, the
lesser likelihood of collision. This value should be set to a smaller increment for higher
priority traffic. Reduce the value when traffic on the WLAN is anticipated as being smaller.
CW Max The contention window maximum value is the maximum amount of time the MU waits
before transmitting when there is no other data traffic on the network. The longer the
interval, the lesser likelihood of collision, but the greater propensity for longer transmit
periods.
AIFSN The AIFSN is the minimum interframe space between data packets transmitted for the
selected Access Category. This value should be set to a smaller increment for higher
priority traffic to reduce packet delay time.
TXOPs Time 32usec The TXOPs Time is the interval the transmitting MU is assigned for transmitting. The
default for Background traffic is 0. The same TXOPs values should be used for either the
802.11a/n or
802.11b/g/n radio, there is no difference.
TXOPs Time ms TXOP times range from 0.2 ms (background priority) to 3 ms (video priority) in a 802.11a/n
network, and from 1.2 ms to 6 ms in an 802.11b/g/n network. The TXOP bursting
capability greatly enhances the efficiency for high rate traffic such as streaming video.