Description: A sequence number used to indicate that the topology link table needs to be read again. Whenever the SNMP agent is restarted, this value will be reset to 0 (zero). The value will be incremented by one whenever a change to either table has been made. This number will also be sent in the umc1TrapTopologyChange trap and can be used to determine if any traps have been lost. The 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.