This is a catch-all counter for RADIUS packets received from this server on the authentication port that were discarded for a reason not covered by the more specific malformed, bad-authenticator, or unknown-type counters. Because it's the residual everything-else bucket, an admin should treat a rising value here as a cue to check the switch's system/RADIUS event log for the specific drop reason, since this counter itself won't say why. For example, packets arriving after the request they correspond to has already timed out and been purged from the client's pending-request table would typically be dropped and counted here rather than under a more specific error type.