I'm running a WLAN infrastructure dispersed over multiple sites, which all run a local 440x WLC. One site is the main site and runs a backup WLC which can take over any site's APs in case a remote WLC shoud fail.
Here's my question: In order for failover and AP Fallback to work properly, do all WLCs need to have all WLCs configured in the Mobility Group section? In other words, do the APs rely on the Mobility Group feature to get informed when their primary WLC has come back?
I ask because I had problems with the AP Fallback functionality when simulating a WLC failure. Otherwise, I wouldn't need Mobility Group functionality since the sites are geographically separated.
The key piece is to have the units in the same mobility group. This is required for failover to occur quickly. It is a key requirement of some code enhancements done to speed up the failover process. I think this was done in 4.1 code first.