This is the maximum number of times, from 1 to 10, the device resends an Access-Request message to a single AAA server before giving up and declaring authentication failed for that server. This matters because it trades resilience against transient packet loss for speed of failing over to another server: more retries tolerate a flaky link but delay detection of a truly dead server. For example, on a AAA server reached over an unreliable link, an administrator might raise aaaServerRetry above the default of 3 so a couple of dropped UDP packets don't needlessly fail a login attempt.