Refer to the exhibit. A client roams between two APs that are registered to two different controllers, where each controller has an interface in the client subnet. Both controllers are running AireOS. Which scenario explains the client roaming behavior?
A. Controllers exchange mobility control messages (over UDP port 16666) and the client database entry is moved from the original controller to the new controller.
B. Controllers do not exchange mobility control messages (over UDP port 16666) and the client database, entry is not moved from the original controller to the new conrtoller.
C. Controllers exchange mobility control messages (over UDP port 16666) and a new client session is started with the new controller.
D. Controllers exchange mobility control messages (over UDP port 16666) and the client database entry is tunneled from the original controller to the new controller.
https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-2/config-guide/b_wl_17_2_cg/mobility.html
When a client joins an access point associated with a new controller, the new controller exchanges mobility messages with the original controller, and the client database entry is moved to the new controller. New security context and associations are established if necessary, and the client database entry is updated for the new access point. This process remains transparent to the user.
A seems to be correct for an inter-controller L2 roam:
https://www.youtube.com/watch?v=T9MjmyKxlYU&t=1m39s (Wireless Mobility Concepts)
Controllers in a mobility list communicate with each other by controlling information over a well-known User Datagram Protocol (UDP) port and exchanging data traffic through an EoIP tunnel.
So the correct answer is D…
Not in L2 roaming. Answer is A