Patent ID: 6147966
Filing Date: 2000-11-14
Classification: H04L,H04Q

Abstract:
A method of determining an additional route in a fully or partly meshed communications network of nodes, the method comprising the steps of:determining in accordance with a respective predetermined master/slave relationship, at each of a pair of the nodes, between which pair there is an existing route, the one node of said pair which is to act as master end node with respect to said existing route and the other node which is to act as slave end node, said determining step being initiated in response to receipt, at each of said pair of nodes, of a signal indicating that an additional route is required in respect of said existing route;sending from said one node to its neighbouring nodes a forward route-finder signature for said existing route;receiving at a node a said forward route-finder signature, determining whether such receiving node is the slave end node for said existing route and, in the event that it is not, forwarding such received forward route-finder signature to its neighbouring nodes;determining at said other node, upon the expiry of a predetermined timeout triggered by receipt of-said signal, a potential additional route and sending from said other node on said potential additional route a route confirmation signature identifying said potential additional route; andstoring details of said potential additional route at said one node upon receipt thereat of the route confirmation signature;and the method being characterised by the steps of:responding at said other node, in the event that at said timeout a potential additional route has not been determined, and in the event that said other node has sent a said route confirmation signature but has received a backtrack signature indicative of insufficient capacity for said potential additional route at an intermediate node on said potential additional route, by switching to act as master end node with respect to said existing route;sending from said other node to its neighbouring nodes a reverse route-finder signature for said existing route; andresponding at said one node to receipt thereat of said reverse route-finder signature to switch to act as slave end node with respect to said existing route, to determine a respective potential additional route, and to send a corresponding route confirmation signature.