Cisco Systems OL-8335-02 manual Enabling 7920 Support Mode

Chapter 6 Configuring WLANs

Configuring Wireless LANs

Enabling 7920 Support Mode

The 7920 support mode contains two options:

•Support for 7920 phones that require call admission control (CAC) to be configured on and advertised by the client device (these are typically older 7920 phones)

•Support for 7920 phones that require CAC to be configured on and advertised by the access point (these are typically newer 7920 phones)

Note When access-point-controlled CAC is enabled, the access point sends out a Cisco proprietary CAC Information Element (IE) and does not send out the standard QBSS IE.

Enter this command to enable 7920 support mode for phones that require client-controlled CAC:

config wlan 7920-support client-cac-limit {enabled disabled} wlan-id

Note You cannot enable both WMM mode and client-controlled CAC mode on the same wireless LAN.

Enter this command to enable 7920 support mode for phones that require access-point-controlled CAC:

config wlan 7920-support ap-cac-limit {enabled disabled} wlan-id

QBSS Information Elements Sometimes Degrade 7920 Phone Performance

If your wireless LAN contains both 1000 series access points and Cisco 7920 wireless phones, do not enable the WMM or AP-CAC-LIMIT QBSS information elements. Do not enter either of these commands:

config wlan 7920-support ap-cac-limit enable wlan-id

config wlan wmm [allow require] wlan-id

The information sent by 1000 series access points in the WMM and AP-CAC-LIMIT QBSS information elements is inaccurate and could result in degradation of voice quality 7920 wireless phones. This issue does not affect the CLIENT-CAC-LIMIT QBSS IE, which you enable using this command:

config wlan 7920-support client-cac-limit enable wlan-id

The CLIENT-CAC-LIMIT QBSS IE is the only QBSS IE that should be used in networks containing both 1000 series access points and 7920 wireless phones.

Cisco Wireless LAN Controller Configuration Guide

6-10 OL-8335-02