Two-stage reconnect system and method

A method of re-routing one or more of a plurality of connections through an explicitly routed network, the plurality of connections sharing a common head node, the method comprising:

• categorizing each of said plurality of connections to be either a high priority connection or a low priority connection;
• for each high priority connection, pre-configuring a corresponding alternate connection through the network;
• upon a failure of a resource in the network:
• a) re-routing each high priority connection which uses the resource to use its corresponding alternate connection;
• b) initially re-routing each low priority connection which uses the resource to at least one reduced constraint connection through the network;
• c) for each low priority connection which has been re-routed to a reduced constraint connection, establishing a respective fully constrained connection through the network, or re-configuring the reduced constraint connection to be a respective fully constrained connection;
• d) subsequently re-routing each low priority connection which has been re-routed to the respective fully constrained connection through the network.

A network node comprising:

• a plurality of user cards allowing connection of external devices to the network node;
• a plurality of network cards allowing connection of the network node to other parts of a network of which the network node forms a part;
• a connection manager adapted to manage plurality of connections initiated at the network node through the network of which the network node forms a part;
• a multi-constraint router adapted to calculate routes through the network of which the network node forms a part;
• the network node being adapted to maintain resource usage information identifying for each of a plurality of resources in the network which of said plurality connections use the resource;
• upon a failure of a resource in the network, the network node being adapted to:
• a) re-route each connection which uses the resource to a corresponding reduced constraint connection;
• b) for each connection which has been re-routed, establish a respective fully constrained connection through the network;
• c) subsequently re-route each connection which has been re-routed to the respective fully constrained connection through the network.

A network node comprising:

• a plurality of user cards allowing connection of external devices to the network node;
• a plurality of network cards allowing connection of the network node to other parts of a network of which the network node forms a part;
• a connection manager adapted to manage a plurality of connections initiated at the network node through the network of which the network node forms a part;
• a multi-constraint router adapted to calculate routes through the network of which the network node forms a part;
• the network node being adapted to maintain resource usage information identifying for each of a plurality of resources in the network which of said plurality connections use the resource;
• the network node being adapted to maintain priority information for each of said plurality of connections enabling each connection to be categorized to be either a high priority connection or a low priority connection;
• for each high priority connection, the network node being adapted to pre-configuring a corresponding alternate connection through the network;
• upon a failure of a resource in the network, the network node being adapted to:
• a) re-route each high priority connection which uses the resource to use its corresponding alternate connection;
• b) initially re-route any low priority connections which uses the resource to at least one reduced constraint connection through the network;
• c) for each low priority connection which has been re-routed, establish a respective fully constrained connection through the network;
• d) subsequently re-route each low priority connection which has been re-routed to the respective fully constrained path through the network.