366 V7122 GatewayUser GuideA carrier-grade alarm system is characterized by the following: The device has a mechanism that allows a manager to determine which alarms arecurrently active in the device. That is, the device maintains an active alarm table. The device has a mechanism to allow a manager to detect lost alarm raise and clearnotifications [sequence number in trap, current sequence number MIB object]. The device has a mechanism to allow a manager to recover lost alarm raise and clearnotifications [maintains a log history]. The device sends a cold start trap to indicate that it is starting. This allows the EMS tosynchronize its view of the device's active alarms.When the SNMP alarm traps are sent, the carrier-grade alarm system does not add or deletealarm traps as part of the feature. This system provides the mechanism for viewing of historyand current active alarm information.Active Alarm TableThe device maintains an active alarm table to allow a manager to determine which alarmsare currently active in the device. Two views of the active alarm table are supported by theagent: acActiveAlarmTable in the enterprise acAlarm alarmActiveTable and alarmActiveVariableTable in the IETF standard ALARM-MIB(rooted in the AC tree)The acActiveAlarmTable is a simple, one-row per alarm table that is easy to view with a MIBbrowser.The ALARM-MIB is currently a draft standard and therefore has no OID assigned to it. In thecurrent software release, the MIB is rooted in the experimental MIB subtree. In a futurerelease, after the MIB has been ratified and an OID assigned, it is to move to the official OID.Alarm HistoryThe device maintains a history of alarms that have been raised and traps that have beencleared to allow a manager to recover any lost, raised or cleared traps. Two views of thealarm history table are supported by the agent: acAlarmHistoryTable in the enterprise acAlarm nlmLogTable and nlmLogVariableTable in the standard NOTIFICATION-LOG-MIBAs with the acActiveAlarmTable, the acAlarmHistoryTable is a simple, one-row-per-alarmtable that is easy to view with a MIB browser.
