Refer to the exhibit.
An administrator implements an L2 cluster of Aruba Mobility Controllers (MCs) as shown in the exhibit. An external RADIUS AAA server authentication clients associated with the Active User Anchor Controller (A-UAC), where the NAS IP address sent from Controller B is 10.254.1.2.
By default, what happens to the user's session when it is handed over to the Standby UAC (S-UAC) after a failover?
When a user's session is handed over to the Standby User Anchor Controller (S-UAC) in an L2 cluster of Aruba Mobility Controllers after a failover, the user's session remains active. However, the AAA server cannot implement RADIUS Change of Authorization (CoA). This is due to the fact that CoA messages are processed based on the NAS IP address, which would still reference the original controller (Controller B), and there is no mechanism in place here to update the NAS IP address to the S-UAC post-failover. Therefore, while the session remains active, the AAA server is not able to recognize the new controller for CoA messages.
I think it is B, because there is no VRRP-Configuration mentioned and that is needed to receive the CoA in case of a MC failure