AAA, NAC, Guest Access & BYOD

Virtual IP address is shared between two nodes in a cluster and the behavior of the Virtual IP(VIP) address is as follows:

-Virtual IP(VIP) stays with the configured Primary node until it fails. This failure can be simulated by stopping the VIP service.
-Upon failure of the configured Primary, the configured Secondary takes over the VIP. It does a gratuitous ARP to update ARP caches and emits system events to indicate the takeover.
-When the primary is back on line – this can be simulated by starting VIP service on the primary, it takes back the VIP. It does a gratuitous ARP to update ARP caches and emits system events to indicate the takeover.

 
The only exception to this is when you have publisher redundancy configured. In this case, if you shutdown the publisher long enough, the configured standby promotes itself as publisher. The original publisher is dropped from cluster during this promotion. Since the original publisher is now out of cluster, any VIPs for which it was configured as the primary are NOT released back to it even if you bring up that machine again. The VIP service on the original publisher will be stopped and it will refuse to start if you try to start it manually.

 
To get the original publisher back into the cluster, you have to reset its DB and join it back to the cluster. After this joining, you can manually start the VIP service on this node, and it will take back ownership of any VIPs for which it was configured as master.