Cisco 2100 Series Configuration Manual page 343

Chapter 6 Configuring WLANsWireless Device Access
The 7920 support mode has two options:
–
–
You can use the controller GUI or CLI to configure QBSS. QBSS is disabled by default.
OL-17037-01
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)
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.
Cisco Wireless LAN Controller Configuration Guide
Configuring WLANs
6-33