Patent ID: 7808961

Claim:
A radio communication system comprising: a public packet-switched network; a plurality of radio communication networks, each comprising a gateway; a terminal capable of establishing packet connection with the plurality of radio communication networks; a correspondent node which performs packet communication with the terminal over the public packet-switched network; and a router which manages a destination address of the terminal, the destination address changing in accordance with movement of the terminal; wherein the terminal specifies, for each port number of the terminal, a gateway that relays packets sent from the correspondent node to the terminal and sets information which specifies the gateway in a main gateway selected from the plurality of gateways; the router outputs packets which are input from the correspondent node and are directed to the terminal to the main gateway; the main gateway outputs packets directed to the terminal to a transfer-destination gateway associated with an IP address specified for each port number of the terminal; the gateway outputs packets which are input from the main gateway and are directed to the terminal to the terminal; and the terminal outputs packets directed to the correspondent node to the transfer-destination gateway associated with the IP address specified for each port number.