TECHNIQUE FOR PROTECTING A MULTIPOINT-TO-MULTIPOINT TAG SWITCHING PATH IN CONNECTED MODE UPON A FAILURE AFFECTING A GIVEN NODE OF THE PATH

摘要

The invention relates to a technique for protecting a multipoint-to-multipoint primary tag switching path in connected mode upon a fault affecting a given node (104) of the path in a tag switching communication network, through a connected-mode multipoint-to-multipoint backup tag switching path. The network comprises routing nodes organized along the primary path, the primary path being adapted for making a plurality of end nodes communicate with one another and comprising branches linking the routing nodes pairwise from a root node up to the end nodes. A method of initiating a protection comprises the following steps implemented by a protector node (101) upstream of the given node, the backup path being adapted for making a set of protector nodes consisting of the upstream node and of the nodes (105, 106) downstream of the given node communicate with one another; a step of assigning a backup tag to be associated by the protector nodes of the set with the packets destined to be routed by one of the branches of the primary path linking the given node to one of the protector nodes of the set and routed through the backup path upon the fault; a step of dispatching a request for protection to one of the protector nodes downstream of the given node, said protection request indicating the primary path, the backup path and the assigned backup tag, the step of dispatching being iteratively repeated for the set of protector nodes downstream of the given node.