Alarm state is maintained by PDSN by comparing usrVHAFailedSessionsValue with critical, major, and clear alarm thresholds. IF alarm state changes to critical, AND usrVHAFailedSessionsTrapsEnabled is true THEN usrVHAFailedSessionsCriticalAlarm TRAP will be sent. IF alarm state changes to major, AND usrVHAFailedSessionsTrapsEnabled is true THEN usrVHAFailedSessionsMajorAlarm TRAP will be sent. IF alarm state changes to clear, AND usrVHAFailedSessionsTrapsEnabled is true THEN usrVHAFailedSessionsCriticalAlarm TRAP will be sent. IF alarm state changes, THEN usrVHAFailedSessionsAlarmTime is updated with the current time regardless of usrVHAFailedSessionsTrapsEnabled and usrVHAFailedSessionsAlarmChanges is incremented. This allows alarm state and time information to be retrieved by SNMP management stations that don't support SNMP traps or when traps are intentionally disabled to reduce trap processing load on the SNMP management station. Writing a 'clear' value will force the alarm state to go to 'clear'. This will count as a state change and cause a trap if the state was 'major' or 'critical'. This step conceptually occurs before comparing the alarm thresholds. If major or critical thresholds are exceeded, the appropriate state change and trap occur. This means that writing 'clear' may cause 0, 1, or 2 alarm state changes and traps.