Abstract: A translation apparatus retains a first correlation between a Mobile IPv6 terminal's home address and virtual IPv4 address. When the Mobile IPv6 terminal transmits a packet to said IPv6 network with a care-of address specified as the packet's source address and a home address specified in an extension header, the translation apparatus changes the packet's source address to a virtual IPv4 address that corresponds to the packet's home address in accordance with the first correlation, and then transmits the packet to an IPv4 network. Mobile IPv6 terminal-to-IPv4 terminal communication can then be established between an IPv6 network to which Mobile IPv6 terminals are connected and an IPv4 network to which IPv4 terminals are connected.

Abstract: A method of relaying data between a first terminal device connected to a first network and a second terminal device connected to a second network comprises: searching in a storing device based on location information accompanying data received from the first terminal device or the second terminal device, the storing device storing location information indicative of a location of at least the first terminal device; as a result of the searching, if the location information exists in the storing device, converting the location information accompanying the data so that the location information stored in the storing device becomes a new location information of the data; and sending the data accompanied with the location information having been converted to the second terminal device or the first terminal device.

Abstract: A translation apparatus retains a first correlation between a Mobile IPv6 terminal's home address and virtual IPv4 address. When the Mobile IPv6 terminal transmits a packet to said IPv6 network with a care-of address specified as the packet's source address and a home address specified in an extension header, the translation apparatus changes the packet's source address to a virtual IPv4 address that corresponds to the packet's home address in accordance with the first correlation, and then transmits the packet to an IPv4 network. Mobile IPv6 terminal-to-IPv4 terminal communication can then be established between an IPv6 network to which Mobile IPv6 terminals are connected and an IPv4 network to which IPv4 terminals are connected.

Abstract: A method of relaying data between a first terminal device connected to a first network and a second terminal device connected to a second network comprises: searching in a storing device based on location information accompanying data received from the first terminal device or the second terminal device, the storing device storing location information indicative of a location of at least the first terminal device; as a result of the searching, if the location information exists in the storing device, converting the location information accompanying the data so that the location information stored in the storing device becomes a new location information of the data; and sending the data accompanied with the location information having been converted to the second terminal device or the first terminal device.