Patent ID: 7725592

Claim:
A communication system having a service handoff function, in which in accordance with control information from a user terminal device, a service can be received while being handed off to a desired transfer destination terminal device, the communication system comprising: a correspondent node delivering communication data which can be executed by a predetermined application; a proxy server device which receives the communication data while holding a session with the correspondent node and executes the application, and further transfers the service provided by the application to the transfer destination terminal device; the transfer destination terminal device capable of outputting at least part of the service transferred from the proxy server device; and the user terminal device which can be carried by a user, wherein the user terminal device prepares control information; wherein each transfer destination terminal device comprises a terminal specific information transmission unit for transmitting the control information; and wherein the user terminal device transmits the control information to the proxy server device, and based on the control information, the proxy server device selects the most effective protocol, switches the transfer destination terminal device, providing the service to perform service handoff to the selected protocol; wherein the user terminal device comprises a transfer destination terminal device selecting section which automatically selects the transfer destination terminal device, based on transfer destination terminal device selection information, and transmits the control information according to the selection in the transfer destination terminal device selecting section; wherein the user terminal device comprises a distance detection section detecting a distance to the transfer destination terminal device, and uses the detection result of the distance detection section as the transfer destination terminal device selection information; wherein the transfer destination terminal device comprises a terminal-specific information sending section which sends performance information of a network line of a relevant device with the proxy server and/or hardware information of the relevant device; and the user terminal device receives the terminal-specific information from the terminal-specific information sending section, and uses the terminal-specific information as the transfer destination terminal device selection information.