Patent ID: 8467400

Claim:
A route setup server that determines a communication route of a flow in a communication network that includes a plurality of nodes, said route setup server comprising: a storage unit in which next hop information is stored, wherein said next hop information indicates, with respect to each of said plurality of nodes, a candidate of a next hop node being a forwarding destination of a data; and a route designing unit configured to design, in response to a route setup request specifying a source node and a destination node of a flow, a communication route from said source node to said destination node, wherein said route designing unit comprises: a next hop determination unit configured to execute next hop determination processing with reference to said next hop information; a loop detection unit; and a loop removal unit, wherein in said next hop determination processing, said next hop determination unit randomly selects one next hop node from said candidate of said next hop node regarding a target node and updates said target node to said selected one next hop node, wherein said next hop determination unit determines said communication route one-hop by one-hop by initializing said target node to said source node and then repeating said next hop determination processing until said target node becomes said destination node, wherein said loop detection unit checks whether or not a current target node overlaps with a past target node to detect a loop on said communication route determined by then, wherein if said loop is detected, said loop removal unit removes said loop by turning said target node back to any past target node, and wherein after said loop is removed, said next hop determination unit starts over said next hop determination processing from said any past target node.