D-Link Unified Access System
Software User Manual
02/15/2011
Page 162
Document 34CS3000-SWUM104-D10
WMM Mode
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 D-Link Unified Access System control
downstream
traffic flowing from the access
point to client station (AP EDCA parameters) and the
upstream
traffic flowing from the
station to the access point (station EDCA parameters).
Disabling WMM deactivates QoS control of station EDCA parameters on
upstream
traffic flowing from the station to the access point
With WMM disabled, you can still set some parameters on the downstream traffic
flowing from the access point to the client station (AP EDCA parameters).
To disable WMM extensions, click
Disabled
.
To enable WMM extensions, click
Enabled
.
Queue
Queues are defined for different types of data transmitted from station-to-AP:
Data 0 (Voice)
Highest priority queue, minimum delay. Time-sensitive data such as VoIP and
streaming media are automatically sent to this queue.
Data 1(Video)
Highest priority queue, minimum delay. Time-sensitive video data is automatically sent
to this queue.
Data 2 (best effort)
Medium priority queue, medium throughput and delay. Most traditional IP data is sent to
this queue.
Data 3 (Background)
Lowest priority queue, high throughput. Bulk data that requires maximum throughput
and is not time-sensitive is sent to this queue (FTP data, for example).
AIFS
(Inter-Frame Space)
The
Arbitration Inter-Frame Spacing
(AIFS) specifies a wait time (in milliseconds) for
data frames.
Valid values for AIFS are 1 through 255.
cwMin
(Minimum Contention
Window)
This parameter is input to the algorithm that determines the initial random backoff wait
time ("window") for retry of a transmission.
The value specified in the
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 1023. The value for
cwMin can be equal to or lower than the value for cwMax.
cwMax
(Maximum Contention
Window)
The value specified in 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 1023. The value for
cwMax can be equal to or higher than the value for cwMin.
Table 60: QoS Settings (Cont.)
Field
Description
