How long does it take for WLC to forget client's AP Group mapping after disassociation?

[tdennehy]

Scenario:

Building A has same WLAN name as Building B.  Buildings both use AP Groups to map the same named WLAN to different VLANs.

All clients were powered up first time in Building A, depleting the IP subnet of addresses.  Clients moved to Building B.  They were offline for about 5 minutes - they were powered off, not just closed, etc.

When clients powered back up in Building B, the AP Group mapping appears to have remained, and the clients are obtaining their previously leased IP addresses from Building A.

The question is, how long does the client AP Group mapping remain, and is there a way to purge it?

Thanks in advance!

[Venkatesh Attuluri]

When roaming across LAPs associated to different controllers, the system behaves according to the regular roaming rules.

When a client associates with an AP on the second controller, the client is mapped to the interface specified by the override. If the AP is a member of the same AP group, you have a Layer 2 mobility event.

If the AP is a member of a different AP group, then you have a Layer 3 mobility event. The VLAN is used to determine the mobility event instead of the configured interface of the WLAN.
Suppose that the interface mapping for a WLAN in the AP group table is the same as the WLAN interface. If the WLAN interface is changed, the interface mapping for the WLAN in the AP group table also changes to the new WLAN interface.Default session timeout value is 1800 sec

Suppose that the interface mapping for a WLAN in the AP group table is different from the one defined for the WLAN. If the WLAN interface is changed, then the interface mapping for the WLAN in the AP group table does not change to the new WLAN interface.