D-Link DWS-3000 Series User Manual page 162

D-Link Unified Access System
Field
WMM Mode
Queue
AIFS
(Inter-Frame Space)
cwMin
(Minimum Contention
Window)
cwMax
(Maximum Contention
Window)
Page 162
Table 60: QoS Settings (Cont.)
Description
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.
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).
The Arbitration Inter-Frame Spacing (AIFS) specifies a wait time (in milliseconds) for
data frames.
Valid values for AIFS are 1 through 255.
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.
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.
Software User Manual
02/15/2011
Document 34CS3000-SWUM104-D10