D-Link DWL-3600AP Administrator's Manual page 104

Unified Access Point Administrator's Guide
Field
cwMin
(Minimum Contention
Window)
cwMax
(Maximum Contention
Window)
Max. Burst Length
Wi-Fi Multimedia Settings
Wi‐Fi MultiMedia
D-Link
November 2011
Table 40: QoS Settings (Cont.)
Description
This parameter is input to the algorithm that determines the initial random backoff
wait time (window) for retry of a transmission.
The value specified for Minimum Contention Window is the upper limit (in
milliseconds) of a range from which the initial random backoff wait time is
determined.
The first random number generated will be a number between 0 and the number
specified here.
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 will continue until the size of the random backoff value reaches the
number defined in the Maximum Contention Window.
Valid values for cwMin are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. The value for
cwMin must be lower than the value for cwMax.
The value specified for the Maximum Contention Window is 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.
Once the Maximum Contention Window size is reached, retries will continue until a
maximum number of retries allowed is reached.
Valid values for cwMax are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. The value for
cwMax must be higher than the value for cwMin.
The Max. Burst Length is an AP EDCA parameter and only applies to traffic flowing
from the AP 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 for maximum burst length are 0.0 through 999.
Wi‐Fi MultiMedia (WMM) is enabled by default. With WMM enabled, QoS
prioritization and coordination of wireless medium access is on. With WMM
enabled, QoS settings on the UAP control downstream traffic flowing from the AP 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 AP.
With WMM disabled, you can still set some parameters on the downstream traffic
flowing from the AP to the client station (AP EDCA parameters).
To disable WMM extensions, click Disabled.
To enable WMM extensions, click Enabled.
Configuring Quality of Service
Unified Access Point Administrator's Guide
Page 104