A Max Sessions Server (MSS) automatically detects hardware and
communications failures. Upon detection, counters are adjusted
accordingly to maintain an accurate count of users or groups of users on
a system. A database of unique identifiers for each connection is
maintained, where the unique identifier is a concatenation of a Network
Access Server (NAS) and the connection's incoming NAS node number. If a
user requests permission to log into the system, the MSS first checks the
database to determine if the unique identifier is already logged in. If
so, then a hardware or communications failure has occurred and the MSS
must make the appropriate adjustments to the database and counter.
Additionally, the MSS or an authentication, authorization and accounting
(AAA) server will periodically check to determine if an NAS has ceased
communicating over a particular length of time and relay any failures to
the MSS. If the NAS has experienced a hardware or communications failure,
then the MSS must make the appropriate adjustments to the database and
counters for all sessions logged in from the failed NAS. Finally, the MSS
may broadcast the failure to all MSSs associated with the NAS on the
system.