Got this in my email last night. I think I've been personally hitting CSCtf34858, and not realizing it. (Well, realizing it but not being able to catch/diagnose it, I've known something was wrong since I went to 6.0.196.0) Looks like I'll be upgrading to 7.0.98.0 within the next few days.
https://supportforums.cisco.com/docs/DOC-11722 This Software Advisory Notice is issued against all the above Wireless LAN Controller software versions due to the following bugs: (as a side note, the are marked Severity 1 - catastrophic ) CSCtf34858 Client can't transmit traffic if it reassociates to an AP within 20 sec CSCte89891 Radio may stop transmitting beacons periodically Base Code: 6.0.182.0, 6.0.188.0, 6.0.196.0 Special Build: Following options are available: 1. Move to 7.0.98.0 Release posted on CCO. Please note, 7.0 is a new feature release. 2. Contact TAC to get a 6.0 Special or Beta release with fixes for the bugs below. 3. Wait for the CCO release of 6.0 MR3 (Maintenance Release), which is planned for July/August 2010 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
