Patent ID: 7630317

Claim:
A transmission bandwidth control device for controlling a transmission route for a flow in a network, comprising: a statistical information collecting unit for collecting pieces of statistical information from respective routers connected to the network; a network information database for storing the statistical information collected; a user request processing unit for accepting and processing a flow forwarding request from a user terminal; a route control unit for searching for a route corresponding to the request from the user terminal by referring to the network information database; a load sharing control unit for executing such a load sharing process as to generate router setting information for sharing a transmission load of the network by referring to the network information database; and a router control unit for setting a router based on the route information determined by the route control unit and on the router setting information generated by the load sharing control unit, wherein the route control unit includes a quality guaranteed route searching module searching for quality guaranteed route information corresponding to the flow forwarding request for the forwarding quality guaranteed flow by referring to link statistical information concerning links between the respective routers from the network information database and a quality non-guaranteed route searching module searching for quality non-guaranteed route information corresponding to the flow forwarding request for the forwarding quality non-guaranteed flow, by referring to link statistical information concerning links between the respective routers from the network information database, the load sharing control unit executes the load sharing process by referring to the quality guaranteed route information and the quality non-guaranteed route information, and the router control unit sets the quality guaranteed route and the quality non-guaranteed route in accordance with the searched quality guaranteed route information and quality non-guaranteed route information, wherein in the case where the quality guaranteed route searching module selects such a route as to minimize a cross-over hop count in the network, the quality non-guaranteed route searching module selects such a route as to maximize a residual bandwidth in the network; wherein the quality non-guaranteed route searching module, when selecting a route for a flow that does not guarantee a forwarding quality, uses a ratio of a remaining bandwidth, as a link's residual bandwidth, which is a result of subtracting the bandwidth for the flow that does not guarantee the forwarding quality from a link bandwidth as link's physical bandwidth, with respect to a bandwidth unreserved for the flow that guarantees the forwarding quality.