Resilient PPP/ML-PPP services over multi-chassis APS protected routers

A method for resilient communication services over multi-chassis Automatic Protection Switching (APS) protected routers, comprising:

• all active entities in a working chassis having state information sending that state information to parallel inactive entities in a protection chassis through a multi-chassis APS control link between the working chassis and the protection chassis;
• active entities sending changed state information from said working chassis to said protection chassis through said multi-chassis APS control link upon a state change of said active entities;
• and
• inactive entities requesting current state information from said all active entities through said multi-chassis APS control link when said inactive entities come back up after being down, wherein 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.

A communication method for resilient communication services over multi-chassis Automatic Protection Switching (APS) protected routers, comprising:

• sending one or more packets with one or more corresponding sequence numbers from a plurality of active entities in a working chassis to a plurality of parallel inactive entities in a protection chassis by way of a multi-chassis APS control link passing between said working chassis and said protection chassis;
• receiving said one or more packets with said one or more corresponding sequence numbers at the plurality of parallel inactive entities in said protection chassis;
• sending one or more acknowledgements with said one or more corresponding sequence numbers from said plurality of parallel inactive entities in said protection chassis to said active entities in said working chassis through said multi-chassis APS control link;
• and
• receiving said one or more acknowledgements with said one or more corresponding sequence numbers at said active entities in said working chassis, wherein 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.

A method for resilient communications services over multi-chassis Automatic Protection Switching (APS) protective routers, comprising:

• all active entities in a working chassis having state information sending that state information to parallel inactive entities in a protection chassis through a multi-chassis APS control link that connects the working chassis and the protection chassis;
• determining that a control link is down;
• determining that the control link that was down has come back up by receipt of an acknowledgment with a corresponding sequence number;
• and
• all active entities in the working chassis again sending the state information to the parallel inactive entities in the protection chassis through the multi-chassis APS control link, wherein 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.