This read-only OID reports whether the APS pair is configured as 'revertive' (traffic returns to the working port after it recovers) or 'nonrevertive' (traffic stays on protection until manually switched). Revertive mode causes traffic to flap when a recovered link is reactivated; nonrevertive avoids flapping but requires manual intervention to return to primary. In nonrevertive mode, even if the primary link comes back online, traffic continues on the protection port indefinitely.