This counts the number of times an Access-Request to this server got no response at all within the retry window, as opposed to getting an explicit reject, malformed response, or bad authenticator. Per the object's own description, each timeout that leads to a same-server retry also increments the Retransmissions counter, and each timeout that leads the client to try a different server also increments that other server's Requests counter, so an admin can trace a single flaky authentication attempt across multiple counters on multiple table rows. For example, one supplicant's failed login against a dead primary server could show up as +1 here, +1 on Retransmissions from a same-server retry, and +1 on the backup server's Requests counter from failover, all from one login attempt.