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Cisco Wireless LAN Controller Configuration Guide
OL-8335-02
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.
