Are your controllers in the same mobility group? (Controller|General|Default Mobility Name)

You can also check under Controller|Mobility Management|Mobility Groups to see if other controllers are set up to exchange Mobility Management info.

If you are in the same Mobility Management group then when failover to another member/controller in that group occurs and the AP Group name is the same on both controllers the APs should automatically join that AP Group name on the controller they failed over to.

Our implementation (still in the early stages) includes 8 WiSMs Controllers that are in the same Mobility Management group and will fail across campuses if we lose a WiSM module or chassis.

We will be using smaller controllers (4402's) at remote sites with their own Mobility Name. That is to prevent constantly exchanging client info with other controllers over wan links. If/when those failover to the main campus they will wind up being in the AP Group default-group on the WiSM environment.

Try this ...

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Wireless%20-%20Mobility&topic=General&topicID=.ee6e8b8&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.2cd35b66/0#selected_message

i did come across but however i believe the vlan tag cause the failover problem . I wrote this on the link .U can come take a look at this.

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Wireless%20-%20Mobility&topic=Wireless%20IP%20Voice%20and%20Video&topicID=.ee6e8bc&fromOutline=&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.2cd35fef