Wireless
Quality of Service
Cisco Small Business WAP371 Wireless Access Point Administration Guide
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5
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Custom—Enables you to choose custom EDCA parameters.
These four queues are defined for different types of data transmitted from WAP-to-station. If
you choose a Custom template, the parameters that define the queues are configurable;
otherwise, they are set to predefined values appropriate to your selection. The four queues are:
•
Data 0 (Voice)—High priority queue, minimum delay. Time-sensitive data such as VoIP
and streaming media are automatically sent to this queue.
•
Data 1 (Video)—High 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).
STEP 3
Configure the following EDCA and Station EDCA parameters:
NOTE
These parameters are configurable only if you selected Custom in the previous
step.
•
Arbitration Inter-Frame Space—A wait time for data frames. The wait time is measured
in slots. Valid values for AIFS are 1 through 255.
•
Minimum Contention Window—An input to the algorithm that determines the initial
random backoff wait time (window) for retry of a transmission.
This value is the upper limit (in milliseconds) of a range from which the initial random
backoff wait time is determined.
The first random number generated is 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 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 1023. 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.
