Cisco Small Business AP541N Administration Manual page 100

Wireless
Configuring Quality of Service (QoS)
Cisco AP541N Dual-band Single-radio Access Point Quick Start Guide
Table 24 QoS Parameters (Continued)
Field
Station EDCA Parameters
Queue
AIFS
(Inter-Frame Space)
cwMin
(Minimum
Contention Window)
Description
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 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 wait time for data transmission during a
period of contention for access point resources. The value
specified here in the Minimum Contention Window is the
upper limit 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 timer expires before the data frame is sent, a retry
counter is incremented and the random backoff value is
doubled. Doubling will continue until the size of the random
backoff value reaches the number defined in the Maximum
Contention Window.
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