A transport control server coupled to a plurality of nodes in a network through which a plurality of traffics passes through is provided. The transport control server is configured to receive bandwidth information from each of the nodes when the traffics pass through the nodes. For each of the traffics, the transport control server calculates bandwidths at an entry edge node and at an exit edge node based on the received bandwidth information. The transport control server defines as a first traffic, based on the calculated bandwidths at the entry edge node and the exit edge node, a traffic having a discarded bandwidth that is larger than a first predetermined bandwidth. Also, the transport control server defines as a second traffic, based on the received bandwidth information, a first traffic having a bandwidth at the two or more nodes that exceeds a specified second bandwidth.