Patent ID: 8611220

Claim:
A network system comprising: an appliance and a switch configured to be arranged in a network; and a controller configured to be connected to the appliance and the switch, wherein the switch includes a flow table, wherein each entry of the flow table indicates a match condition and an action to be performed on a packet which matches the match condition, wherein the switch sets an entry in the flow table in response to entry setting information transmitted from the controller, wherein the switch, upon receiving a reception packet, refers to the flow table and carries out an action specified by an entry which matches the reception packet on the reception packet, wherein the appliance has a packet discard function, and when the packet is discarded, transmits packet discard information as information related to the discarded packet to the controller, wherein the controller performs a switch control process in response to the packet discard information, and wherein in the switch control process, the controller selects a target switch from the network, creates entry setting information for instructing the target switch to create an entry such that a packet belonging to the same flow as the discarded packet is discarded, and transmits the created entry setting information to the target switch.