A switch includes at least a first table and a second table different in mapping of egress information of a network and user information to a packet. The first table is searched for a first packet received and operation according to an action corresponding to a search key of the first table is applied to the first packet to convert the first packet to a second packet. The second packet is supplied to the second table. The second table is then searched for the second packet. When the search key of the second table is matched, the operation according to the action corresponding to the search key of the second table is applied to the second packet to convert the second packet to a third packet (refer to FIG. 5).