Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

7920-AP1100-voice call limitation (CAC)


i have an AP1100 (12.3.8JEB1) , several IP Phones 7920 .All is working but i would like to limit tne number of simultaneous calls to 3 for example.There is a function called CAC in the AP with bandwidth limitation (max channel percentage).When all is configured , i still can have more than 3 active calls.

Must i have 7921G ( for TSpec support) to function ?

Must i have a WLSE controller to use this CAC function ?

Thanks for your help.

Cisco Employee

Re: 7920-AP1100-voice call limitation (CAC)

Yes 7920 does not support TSPEC, so will keep making calls.

The 7920 uses QBSS to determine if it can make an outbound call, but nothing to stop incoming calls.

The QBSS threshold is 105 by default. If less than that then can call out.

To adjust this parameter, can use the following command:

dot11 phone dot11e cac-thresh X

But also remember that this QBSS version is CCA based, so will account for more than just # of calls, it will account for entire channel utilization including non-802.11 2.4 GHz devices (i.e. microwaves, ec.) as well as 802.11 devices (APs and clients on same channel).

New Member

Re: 7920-AP1100-voice call limitation (CAC)

Thanks for these precisions.