SNMP traps and informs are two methods that an Network Element (NE) uses to notify an NMS about an autonomous events that occur on the NE. SNMP traps are unacknowledged notifications, while SNMP informs are acknowledged by the recipient (typically a management station). Sometimes SNMP notifications sent by an NE fail to be received by the management station. Typically, when a failure clears, the management station will re-sync its view of the NE state with the actual NE state.
Re-syncs are costly because the management station has to read the entire state of the NE, even if the changes in the state of the NE during the downtime are minimal. To reduce the need a full re-sync, ExtremeXOS adds a notification log to the NE. The log is populated with notifications sent by the NE to management stations. After a network or management station failure, the management station can read the log to see what events occurred during the downtime, thus eliminating the need for a full re-sync.