BUG CSCtt38270: 7925 sometimes takes 1+ second to respond to WPA M1 key message
Friday, September 21, 2012 at 10:54AM
George

Heads up if you're having wireless voice issues with 7925 handsets with WPA2/PSK. Problems with roaming, gap in voice bug.

7925 sometimes takes 1+ second to respond to WPA M1 key message
Symptom:
A wireless phone call may experience a voice gap of 1.5 - 2 seconds when it roams if using WPA2-PSK.

Conditions:
7925G is configured to use WPA2/AES PSK.

Workaround:
Configure some key management method to avoid performing a full WPA2 key exchange
at each roam time. For example, EAP with CCKM, or static WEP.
If using PSK, then reducing the WPA key retransmission timeout (e.g., on a WLC,
via "config advanced eap eapol-key-timeout 250", may ameliorate the problem
somewhat (e.g. bring the outage duration down from 2.5 to 1.7 seconds.)

1.4.3ES.1 containing the fix for CSCtz48689 may be helpful as well.

Further Problem Description:
A wireless packet capture, or a "debug client" on the WLC, will show that the WLC/AP
transmit the M1 key message to the phone (and the capture shows that the phone ACKs
it), but the phone does not send its M2 key. So the WLC/AP have to retransmit the M1 key,
till finally the phone responds.
Status Status 
Terminated 

Severity Severity 
3 - moderate 

Last Modified Last Modified 
In Last 2 weeks 

Product Product 
Cisco Unified IP Phone 7900 Series 

Technology Technology 
Wireless, Mobile 

1st Found-In 1st Found-in 
1.4(2)
1.4(1.1.1.7) 

 


Article originally appeared on my80211.com (http://www.my80211.com/).
See website for complete article licensing information.