This orders which of potentially several configured user-login authentication servers gets tried first, letting an admin ensure administrative logins always attempt a fast, trusted local server before falling back to a remote one, entirely independent of whatever priority ordering exists in the general client table for other RADIUS purposes. For example, giving a local, on-site RADIUS server priority 1 for user logins specifically ensures CLI access still authenticates quickly even if a remote, higher-latency backup server with priority 2 is also configured.