This controls whether this pseudowire pair uses automatic reversion: with reversion on(1), once the primary pseudowire recovers from a failure it is held down for cienaCesMplsPwRevertTime seconds before traffic automatically switches back from the backup to the primary, while with reversion off(2) traffic stays on the backup until an operator manually issues a switchover command. This setting directly determines whether restoring the primary path after a fiber repair, for instance, will automatically bring traffic back onto it or whether it will silently continue riding the backup path indefinitely until someone notices and intervenes. A network with reversion off(2) that suffered a failure weeks ago may still be running entirely on its backup pseudowire even though the primary has long since been repaired, which is worth actively checking for.