AAG session-timeout

Question

May I confirm session-timeout checking within replica is using protocol ping ?? to end point address ?
or ping to endpoint tcp port ?

Answer 1

Yes the replicas use ping to gauge whether other replica is reachable or not and ping internally uses ICMP protocol to establish connection.

The ping would be to the server not to any port. Ping internally uses what is called as ECHO functionality to check if other server is alive.