Cisco 2504 Specifications download pdf (Page 72)

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Cisco Wireless LAN Controller Configuration Guide

OL-21524-02

Chapter 4 Configuring Controller Settings

Configuring Voice and Video Parameters

Three parameters on the controller affect voice and/or video quality:

• Call admission control

• Expedited bandwidth requests

• Unscheduled automatic power save delivery

Each of these parameters is supported in Cisco Compatible Extensions (CCX) v4 and v5. See the

“Configuring Access Point Groups” section on page 7-55 for more information on CCX.

Note CCX is not supported on the AP1030.

Traffic stream metrics (TSM) can be used to monitor and report issues with voice quality.

Call Admission Control

Call admission control (CAC) enables an access point to maintain controlled quality of service (QoS)

when the wireless LAN is experiencing congestion. The Wi-Fi Multimedia (WMM) protocol deployed

in CCXv3 ensures sufficient QoS as long as the wireless LAN is not congested. However, in order to

maintain QoS under differing network loads, CAC in CCXv4 is required. Two types of CAC are

available: bandwidth-based CAC and load-based CAC.

Bandwidth-Based CAC

Bandwidth-based, or static, CAC enables the client to specify how much bandwidth or shared medium

time is required to accept a new call and in turn enables the access point to determine whether it is

capable of accommodating this particular call. The access point rejects the call if necessary in order to

maintain the maximum allowed number of calls with acceptable quality.

The QoS setting for a WLAN determines the level of bandwidth-based CAC support. To use

bandwidth-based CAC with voice applications, the WLAN must be configured for Platinum QoS. To use

bandwidth-based CAC with video applications, the WLAN must be configured for Gold QoS. Also,

make sure that WMM is enabled for the WLAN. See the “Configuring 802.3 Bridging” section on

page 4-52 for QoS and WMM configuration instructions.

Note You must enable admission control (ACM) for CCXv4 clients that have WMM enabled. Otherwise,

bandwidth-based CAC does not operate properly.

Load-Based CAC

Load-based CAC incorporates a measurement scheme that takes into account the bandwidth consumed

by all traffic types (including that from clients), co-channel access point loads, and collocated channel

interference, for voice applications. Load-based CAC also covers the additional bandwidth consumption

resulting from PHY and channel impairment.

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Cisco 2504 Specifications Page 72