Cisco CUBE HA Design Restrictions

[russell.sage]

I am looking to deploy a pair of C8200 routers as cubes in HA mode. According to the documentation Cisco Unified Border Element Configuration Guide Through Cisco IOS XE 17.5 - High Availability on Cisco 4000 Series ISR and Cisco Catalyst 8000 Series Edge Platforms [Cisco Unified Border Element] - Cisco in the "Restrictions" section it states that "Both active and standby routers must be in the same Data Center and connected to the same physical switch."

I need to put them into two different buildings on a campus connected with fiber as my WAN routers are in different buildings. Is this just a latency issue I can't see why it has be the same physical switch.

[John Steele · Accepted solution]

The restriction on same physical switch is to ensure Layer 2 adjacency and minimal failover complexity or STP convergence delays.