Description: The reason that an initial failover or automatic Bacbone re-configuration was invoked following a fault detected in the backup configuration. This variable returns nofailover(1) if no failover has occurred or if the bus is not configured. It returns autopartitioned(3) if the reason for the failure is that the bus backbone module has autopartitioned, bus-clock-failure(4) if the cause is an internal chassis bus clock failure, internal-tx-failure(5) if the cause is an internal transmit failure, external-ping-failure(6) if the cause is the failure of a ping attempt, and config-change(7) if the backbone modules had to be reset during the current configuration if another backbone was enabled by a means other than hot failover (for example, with the Connectivity Module Bus variable).