Patent ID: 7852758
Filing Date: 2010-12-14
Classification: H04L

Abstract:
1. A path control method for route-controlling a label switch path generated in a network having a plurality of nodes, the network including a routing area 0 where a path originating node is present, and another routing area 1 , the path control method comprising operations of: at the path originating node, computing a route within the routing area at a transit node which has received the label allocation request message, selecting a link different from a restricted link indicated by the restricted link information attached to the label allocation request message; and sending the label allocation request message from the transmit node to the selected link, at a boundary node, which has received the label allocation request message and connects the routing area sending out an updated label allocation request message to which the computed further route information defining the further route is attached as new explicit route information; at the path originating node and the boundary node, using route information of the switch path as the restricted link information; and wherein either an absolute inhibit level which prohibits passage or an extreme inhibit level which restricts passage according to a prescribed rule determined in advance, is set for the restricted link; the transit node selects the link according to either of the inhibit levels the restricted link information has a restricted link list which indicates an inhibit level of the restricted link; and the transit node: selects a link which configures a route with the least number of times of passing through the link indicating an extreme inhibit level when all the restricted link lists indicate an extreme inhibit level; selects a link which configures a route with a less number of hops when there are plural routes which do not pass through the extreme inhibit link; and selects a link which configures a route with the least number of times of passing through the link indicating the extreme inhibit level among routes which do not pass through a link indicating an absolute inhibit level when there is a link indicating one or more absolute inhibit levels in the restricted link list.