Patent ID: 8264951

Claim:
A system for resilient communication services under multi-chassis Automatic Protection Switching (APS) protected routers, comprising: an add-drop multiplexer; a working chassis; a plurality of working lines of communication between the add-drop multiplexer and the working chassis; a protection chassis; a plurality of protection lines of communication between the add-drop multiplexer and the protection chassis; and a multi-chassis APS control link between the working chassis and the protection chassis, wherein active entities in the working chassis send their state information to parallel inactive entities in the protection chassis by way of the multi-chassis APS control link, said active entities send changed state information to the parallel inactive entities through said multi-chassis APS control link upon a state change in said active entities, and said parallel inactive entities that were down request current state information from said active entities through said multi-chassis APS control link when said inactive entities that were down come back up after being down, and Point-to-Point Protocol (PPP) states for the active entities in the working chassis are synchronized with PPP states for the parallel inactive entities in the protection chassis by receipt of an acknowledgment with a corresponding sequence number.