Description: A sequence number used to indicate that the Threshold Crossing Alert History (TCA) Table, umc1SystemTCAHistoryTable, has been modified and it needs to be re-read. Whenever the SNMP agent is restarted, this value will reset to 0(zero). The value will be incremented by one whenever a change to the Threshold Crossing Alert History Table has been made. This number will also be sent in the umc1TrapTCAHistoryTableChange TRAP and can be used to determine if any traps have been lost by the manager. This value will be incremented before the trap is sent.

The maximum value it can assume is 2,147,483,647. An increment, every time it has reached its maximum value, shall cause it to be reset to 1.