A terminal has a radio device TD1 for connection by radio communication, a terminal router CR1, and terminal segment C.1. The radio device TD1 uses a temporary terminal address while being connected to the same base transceiver station segment B.x. In the terminal segment C.1, an application uses a constant terminal specific address. The terminal router CR1 informs a base transceiver station gateway, which relays the communication data and exchange the path information with the data relay devices on the Internet, of the path information that the data communication to the terminal specific address goes through the temporary terminal address.