Patent ID: 6920138

Claim:
A method for performing communications between a first apparatus using an IPv6 as a communication protocol and a second apparatus using an IPv4 as a communication protocol, comprising the steps of: receiving an IPv6 packet from said first apparatus, said IPv6 packet containing an IPv6 address allocated to said second apparatus as a destination address and an IPv6 address of said first apparatus as a source address; converting the IPv6 address allocated to said second apparatus into an IPv4 address of said second apparatus; converting the IPv6 address of said first apparatus and a first TCP/UDP port number contained in said IPv6 packet into a predetermined IPv4 address and a second TCP/UDP port number; creating an IPv4 packet from said IPv6 packet, said IPv4 packet containing the IPv4 address of said second apparatus as a destination address, said predetermined IPv4 address as a source address and the second TCP/UDP port number; and sending said IPv4 packet to said second apparatus.