Patent ID: 8780836

Claim:
A network system, comprising: an appliance configured to perform a packet header rewriting for rewriting header information of packets in accordance with a predetermined rewriting mode; a controller including a storage unit being non-transitory in which shortcut management information indicating said predetermined rewriting mode and a predetermined condition is stored; and a switch connected to said appliance and said controller, wherein said switch includes a flow table, wherein each entry in said flow table specifies an action to be carried out on a packet matching a matching condition; wherein said switch is configured to refer to said flow table upon receiving a packet and to perform an action specified by an entry that matches said received packet on said received packet, wherein said switch transfers a predetermined packet to said appliance, wherein said appliance generates a rewritten packet by carrying out said packet header rewriting on said predetermined packet and forwards said rewritten packet back to said switch, wherein said switch transfers said rewritten packet received from said appliance to said controller, said controller refers to said shortcut management information in response to said rewritten packet, wherein, in a case when said rewritten packet meets said predetermined condition, said controller generates entry setting data which instructs to set a new entry on the basis of a destination of said rewritten packet and said predetermined rewriting mode, and sends said entry setting data to said switch, wherein said new entry indicates that packets belonging to the same flow as said predetermined packet are transferred to said destination without being routed through said appliance, and wherein said switch adds said new entry to said flow table in accordance with said entry setting data received from said controller.