D-Link DWL-3600AP Administrator's Manual page 105

Unified Access Point Administrator's Guide
Field
Station EDCA Parameters
Queue
AIFS
(Inter‐Frame Space)
cwMin
(Minimum Contention
Window)
cwMax
(Maximum Contention
Window)
TXOP Limit
Other QoS Settings
No Acknowledgement
APSD
Note: After you configure the QoS settings, you must click Apply to apply the changes and to save the
settings. Changing some settings might cause the AP to stop and restart system processes. If this
happens, wireless clients will temporarily lose connectivity. We recommend that you change AP
settings when WLAN traffic is low.
D-Link
November 2011
Table 40: QoS Settings (Cont.)
Description
Queues are defined for different types of data transmitted from station‐to‐AP:
• Data 0 (Voice) — H ighest priority queue, minimum delay. Time‐sensitive data
such as VoIP and streaming media are automatically sent to this queue.
• Data 1(Video) — H ighest priority queue, minimum delay. Time‐sensitive video
data is automatically sent to this queue.
• Data 2 (best effort) — M edium priority queue, medium throughput and delay.
Most traditional IP data is sent to this queue.
• Data 3 (Background) — L owest 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 for data frames.
The wait time is measured in slots. Valid values for AIFS are 1 through 255.
This parameter is used by the algorithm that determines the initial random backoff
wait time (window) for retry of a data transmission during a period of contention for
Unified Access Point resources. The value specified here in the Minimum Contention
Window is the upper limit (in milliseconds) of a range from which the initial random
backoff wait time will be 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.
The value specified here 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.
The TXOP Limit is a station EDCA parameter and only applies to traffic flowing from
the client station to the AP. 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 Unified Access Point.
The TXOP Limit maximum value is 65535.
Select On to specify that the AP should not acknowledge frames with QosNoAck as
the service class value.
Select On to enable Automatic Power Save Delivery (APSD), which is a power
management method. APSD is recommended if VoIP phones access the network
through the AP.
Configuring Quality of Service
Unified Access Point Administrator's Guide
Page 105