The value of tmnxOspfNgNbrRestartHelperExitRc indicates the outcome
of the last attempt at acting as a Graceful restart helper for the
neighbor.
none No restart has yet been attempted.
inProgress A restart attempt is currently underway.
completed The last restart completed successfully.
timedOut The last restart timed out.
topologyChanged The last restart was aborted due to
a topology change.