Fault recovery system and method for a communications network

A communications network comprising:

• first and second nodes interconnected by communication links;
• and
• a traffic path established between a source node and a destination node;
• each of said first and second nodes including routing control means for establishing first and second transport paths on a first fault recovery layer between said first and second nodes,
• said first node further including a database for storing identities of said first and second transport paths as a single virtual link as viewed from said source node, said virtual link comprising a series of component links, said first node advertising fault recovery type of said virtual link as being equal to most unreliable fault recovery type of said component links,
• said first and second nodes accommodating said traffic path on a second fault recovery layer through said first transport path, and accommodating said traffic path on said second fault recovery layer through said second transport path when said first transport path is not working properly.

A multi-domain communications network comprising:

• a plurality of network domains interconnected by inter-domain links, each of said network domains including first and second nodes interconnected by inter-node links;
• and
• a traffic path established between a source node and a destination node,
• the first node, of each of said domains establishing first and second parallel transport paths on a first fault recovery layer to the second node of the domain and including a database for storing identities of said first and second parallel transport paths as a single virtual link as viewed from said source node, and accommodating said traffic path on a second fault recovery layer through the first transport path of the domain, said virtual link comprising a series of component links,
• said first node advertising fault recovery type of said virtual link as being equal to fault recovery type of said first and second transport paths,
• said first and second nodes of each of said domains accommodating said traffic path in the second transport path of the domain when the first transport path of the domain is not working properly.

A multi-domain communications network comprising:

• a plurality of network domains interconnected by inter-domain links, each of said network domains including first and second nodes interconnected by inter-node links;
• and
• a traffic path established between a source node and a destination node,
• the first node of each of said domains establishing first and second parallel transport paths on a first fault recovery layer to the second node of the domain and including a database for storing identities of said first and second parallel transport paths as a single virtual link as viewed from said source node, and accommodating said traffic path on a second fault recovery layer through the first transport path of the domain, said virtual link comprising a series of component links,
• said first node advertising fault recovery type of said virtual link as being equal to most unreliable fault recovery type of said component links,
• said first and second nodes of each of said domains accommodating said traffic path in the second transport path of the domain when the first transport path of the domain is not working properly.

A fault recovery method for a communications network in which first and second nodes are interconnected by communication links, the method comprising the steps of:

• establishing first and second parallel transport paths on a first fault recovery layer between the first and second nodes;
• storing identities of said first and second parallel transport paths in a database as a single virtual link as viewed from a source node;
• advertising fault recovery type of said virtual link as being equal to fault recovery type of said first and second transport paths;
• establishing a traffic path between a source node and a destination node;
• accommodating said traffic path on a second fault recovery layer through said first transport path;
• and
• monitoring said first transport path, at said second node, and accommodating said traffic path on said second fault recovery layer through said second transport path when a failure is detected in said first path.

A fault recovery method for a communications network in which first and second nodes are interconnected by communication links, the method comprising the steps of:

• establishing first and second parallel transport paths on a first fault recovery layer between the first and second nodes;
• storing identities of said first and second parallel transport paths in a database as a single virtual link as viewed from a source node, said virtual link comprising a series of component links;
• advertising fault recovery type of said virtual link as being equal to most unreliable fault recovery type of said component links;
• establishing a traffic path between a source node and a destination node;
• accommodating said traffic path on a second fault recovery layer through said first transport path;
• and
• monitoring said first transport path, at said second node, and accommodating said traffic path on said second fault recovery layer through said second transport path when a failure is detected in said first path.