Cisco WAP121 Administration Manual page 100

Wireless
Quality of Service
Cisco Small Business WAP121 and WAP321 Wireless-N Access Point with PoE
If the first random backoff wait time expires before the data frame is sent, a
retry counter is incremented and the random backoff value (window) is
doubled. Doubling continues until the size of the random backoff value
reaches the number defined in the Maximum Contention Window.
Valid values are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. This value must be
lower than the value for the Maximum Contention Window.
• Maximum Contention Window—The upper limit (in milliseconds) for the
doubling of the random backoff value. This doubling continues until either the
data frame is sent or the Maximum Contention Window size is reached.
After the Maximum Contention Window size is reached, retries continue until
a maximum number of retries allowed is reached.
Valid values are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. This value must be
higher than the value for the Minimum Contention Window.
• Maximum Burst (WAP only)—A WAP EDCA parameter that applies only to
traffic flowing from the WAP to the client station.
This value specifies (in milliseconds) the maximum burst length allowed for
packet bursts on the wireless network. A packet burst is a collection of
multiple frames transmitted without header information. The decreased
overhead results in higher throughput and better performance.
Valid values are 0.0 through 999.
• Wi-Fi MultiMedia (WMM)—Select Enable to enable Wi-Fi MultiMedia
(WMM) extensions. This field is enabled by default. With WMM enabled, QoS
prioritization and coordination of wireless medium access is on. With WMM
enabled, QoS settings on the WAP device control downstream traffic
flowing from the WAP device to client station (AP EDCA parameters) and the
upstream traffic flowing from the station to the AP (station EDCA
parameters).
Disabling WMM deactivates QoS control of station EDCA parameters on
upstream traffic flowing from the station to the WAP device. With WMM
disabled, you can still set some parameters on the downstream traffic
flowing from the WAP device to the client station (AP EDCA parameters).
• TXOP Limit (Station only)—The TXOP Limit is a station EDCA parameter and
only applies to traffic flowing from the client station to the WAP device. The
Transmission Opportunity (TXOP) is an interval of time, in milliseconds, when
a WME client station has the right to initiate transmissions onto the wireless
medium (WM) towards the WAP device. The TXOP Limit maximum value is
65535.
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