A network system has: a node performing transmission and reception of a frame based on FCoE (Fiber Channel Over Ethernet); a network; a controller performing management of the node and the network; and a gateway provided with respect to the node. The gateway determines whether a frame received from the node is a control frame or a data frame, forwards the control frame to the controller, and forwards the data frame to the network. The controller performs the management based on the control frame received from the gateway. The network transfers the data frame received from the gateway to a target node without through the controller. The controller comprises a flow management unit that manages a transfer route of the data frame in the network with respect to each flow.