Patent ID: 6259673
Filing Date: 2001-07-10
Classification: H04L,H04Q

Abstract:
A route selection method for selecting a route satisfying a plurality of QoS conditions at a low cost, out of a plurality of routes connecting a start point to an end point via at least one node, said route selection method comprising the steps of:setting conditions to be satisfied for a plurality of QoSs, respectively;inputting an error range permissible for a cost of an unknown optimum route having a minimum cost among routes satisfying all QoS conditions;tentatively setting a cost searching range containing at least the minimum cost;determining whether said cost searching range has been narrowed to a searching possible range, said range being a function of said error range;in response to judgment that said cost searching range has not been narrowed to the searching possible range, deriving a plurality of QoSs of routes leading from the start point to respective nodes at each cost, in order of cost, beginning with a lowest cost within a current cost searching range, on the basis of QoSs of nodes having QoSs already derived;narrowing said cost searching range when a route leading from the start point to the end point and satisfying all of said plurality of QoS conditions is found, on the basis of it cost; andsearching the cost searching range narrowed to said searching possible range for an optimum route.