Patent ID: 7394811
Filing Date: 2008-07-01
Classification: H04L

Abstract:
1. A method of establishing a path in a communications network, the path being for use in a communications session between two endpoints, the method comprising the following steps: advertising information identifying a plurality of path elements or tunnels, the path elements or tunnels being between nodes of said communications network; at a first node associated with the first endpoint sending a communication session setup request message towards a second node associated with the second endpoint or with an intermediate node in the network; at a third node receiving the communication session setup message from the first node, or a message derived therefrom, and replicating the received message to form at least first and second forked communication session setup messages, the third node sending said first and second forked communication setup messages towards said second node along different respective paths; temporarily reserving bandwidth on path elements or tunnels traversed by the communication setup request messages; receiving at the second node at least two communication session setup request messages, these messages comprising, or being derived from, respective ones of said forked communication setup messages; selecting one of said different paths; at the second node sending a communication setup response message along said selected path towards said first node, said communication setup response message converting said temporarily reserved bandwidth on path elements of said selected path into permanent bandwidth reservations; and establishing a path for use in said communications session by storing items of said advertised information, the items identifying path elements or tunnels, associated with a path traversed by said communication setup response message; wherein the communication session setup request message sent by the first node towards the second node defines a partially explicit path between the first and second nodes, and wherein the third node sends the forked communication setup messages in response to the partially explicit path not defining a part of the path between the third node and the second node.