Specifications

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Cisco IOS Command Reference for Cisco Aironet Access Points and Bridges
0L-24115-01
Chapter 2 Cisco IOS Commands for Access Points and Bridges
traffic-class
Command Modes Configuration interface
Command History
Usage Guidelines Use this command to control the backoff parameters for each class of traffic. Backoff parameters control
how the radio accesses the airwaves. The cw-min and cw-max arguments specify the collision window
as a power of 2. For example, if the value is set to 3, the contention window is 0 to 7 backoff slots (2 to
the power
3 minus 1). The fixed-slot arguments specify the number of backoff slots that are counted
before the random backoff counter starts to count down.
For best performance on your bridge links, adjust the CW-min and CW-max contention window settings
according to the values listed in
Table 2-19. The default settings, CW-min 3 and CW-max 10, are best
for point-to-point links. However, for point-to-multipoint links, you should adjust the settings depending
on the number of non-root bridges that associate to the root bridge.
Note If packet concatenation is enabled on the bridge, adjust the CW-min and CW-max settings only
for traffic class 0. Concatenation is enabled by default.
Ta b l e 2-17 Default QoS Radio Traffic Class Definitions for Access Points
Class of Service
Min Contention
Window
Max Contention
Window
Fixed Slot Time Transmit Opportunity
Background 5 10 7 0
Best Effort 5 10 3 0
Video <100ms Latency 4 5 2 3008
1
1. 6016—On access points with IEEE 802.11b radios
Voice <100ms Latency 2 4 2 1504
2
2. 3264—On access points with IEEE 802.11b radios
Ta b l e 2-18 Default QoS Radio Traffic Class Definitions for Bridges
Class of Service
Min Contention
Window
Max Contention
Window
Fixed Slot Time Transmit Opportunity
Background 4 10 7 0
Best Effort 4 10 3 0
Video <100ms Latency 3 4 2 3008
Voice <100ms Latency 2 3 2 1504
Release Modification
12.2(4)JA This command was introduced.
12.2(13)JA This command was modified to support four traffic classes (best-effort,
background, video, and voice) instead of eight (0–7).