Patent ID: 8477601

Claim:
A network management station configured to determine a combination of links to be used by a network control entity configured to perform communication by using a plurality of links, the network management station comprising: a storage unit for storing contract link information including links, measure (throughputs of the links, and measured response times of the links; and service contract information specifying links in use for services, bandwidths in use by the links, minimum response times required for the links, minimum ensured bandwidths required for the links, and priority levels of the services; and a control unit comprising one or more computers, wherein the control unit, when having determined that at least either of the measured throughput and the measured response time of a link in the contract link information does not satisfy the minimum ensured bandwidth or the minimum response time for the link in the service contract information, is configured to: assign a link whose measured throughput in the contract link information satisfies either of its minimum ensured bandwidth and its bandwidth in use in the service contract information and whose measured response time in the contract link information satisfies its minimum response time in the service contract information to each of the services in descending order of priority in the service contract information; create a link usage plan in which the control unit assigns a link whose measured throughput in the contract link information satisfies either of its minimum ensured bandwidth and its bandwidth in use in the service contract information and whose measured response time in the contract link information satisfies its minimum response time in the service contract information to each of the services in descending order of priority in the service contract information; wherein, when a plurality of created link usage plans are available, the control unit is configured to adopt the link usage plan using a combination of links having a higher average degree of attaining conditions as a link whose throughput in the contract link information satisfies either of its minimum ensured bandwidth and its bandwidth in use in the service contract information and whose response time in the contract link information satisfies its minimum response time in the service contract information; wherein, when there are link usage plans having an equal average degree of attaining conditions, the control unit is configured to select a link usage plan, which has a smaller number of times of link switching.