COMMUNICATION ROUTE DETERMINATION SYSTEM AND COMMUNICATION ROUTE DETERMINATION METHOD

A slice manager module selects two network nodes out of network nodes belonging to the network slice and determines the two network nodes as the pair. The slice manager module determines an IP address relating to the network slice for each of the network nodes of the pair. An SDN controller determines, as a part or all of a communication route of the network slice, a communication route between the determined IP addresses. The SDN controller re-determines the communication route between the IP addresses in response to a fact that communication quality of the determined communication route satisfies a predetermined condition.