Patent ID: 7916733

Claim:
An original data communication apparatus in a first local network, the original data communication apparatus comprising: a communication unit configured to carry out data communication with a first other data communication apparatus in the first local network and with a second other data communication apparatus in a second local network, the communication unit configured to carry out data communication using a local address for allowing communication with the first other data communication apparatus in the first local network and carry out data communication using a global address for allowing communication with the first other data communication apparatus in the first local network and the second other data communication apparatus in the second local network; a detection unit configured to detect a connection request from another data communication apparatus; and a control unit configured to, (1) in a case where the another data communication apparatus sending the connection request detected by the detection unit employs the global address and is the first other data communication apparatus in the first local network, request the first other data communication apparatus to carry out communication with the original data communication apparatus by employing the local address without employing the global address, and control the communication unit to carry out the communication with the first other data communication apparatus by employing the local address, and (2) in a case where the another data communication apparatus sending the connection request detected by the detection unit employs the global address and is the second other data communication apparatus in the second local network, control the communication unit to carry out the communication with the second other data communication apparatus by employing the global address.