Patent ID: 7876736

Claim:
An address assignment method for a mobile terminal device capable of accessing both a mobile communication network and a local network simultaneously, the method comprising: transmitting to a gateway device an inquiry message for inquiring information regarding a location on networks of a correspondent of packet communications to be carried out, from the mobile terminal device through the local network; receiving a response message in response to the inquiry message through the local network at the mobile terminal device; acquiring an address to be used by the mobile terminal device in the packet communications with the correspondent according to the response message; assigning the address to a first communication interface for the local network at the mobile terminal device; communicating with the correspondent using the address assigned to the first communication interface; and judging a manner of utilizing first packet communications carried out through the first communication interface and second packet communications carried out through a second communication interface provided for the mobile communication network in the mobile terminal device according to a prescribed policy, when both the first packet communications and the second packet communications are possible.