With a pair of Cisco 5520 WLCs in SSO managing APs and guest traffic anchored to a 3504 in a DMZ, what ensures the EoIP tunnel stays UP after SSO failover?

When a pair of Cisco 5520 WLCs are in SSO and managing APs, with guest traffic anchored to a 3504 WLC in a DMZ, ensuring the EoIP tunnel remains active after an SSO failover is crucial for guest connectivity. The correct approach is to use the mobility MAC address when configuring the mobility peer. This ensures that the mobility tunnel (including EoIP for guest anchoring) is established using a consistent, virtual MAC address that floats between the active and standby WLCs in the SSO pair. If the mobility MAC is not used, the tunnel would be tied to the physical MAC address of the active WLC, causing the tunnel to drop and re-establish during an SSO failover as the physical MAC address changes. Using the same mobility domain on all WLCs is necessary for mobility to function but doesn't specifically address tunnel persistence during SSO failover. Enabling the default gateway reachability check is for network connectivity monitoring, not tunnel persistence. Configuring back-to-back connectivity on RP ports is for redundant WLC-to-WLC communication within the same site, not for maintaining mobility tunnels across different WLCs during SSO failover.