Patent ID: 6907037

Claim:
A communicating apparatus connected to both of an IPv4 network and an IPv6 network, comprising: an IP transmitting/receiving unit for executing transmittance/reception of an IPv4 packet with respect to said IPv4 network and executing transmittance/reception of an IPv6 packet with respect to said IPv6 network, an IP multicast membership group managing unit for holding IPv4 multicast addresses of a multicast group on said IPv4 network, said communicating apparatus being a member of said multicast group, a for-conversion IP address holding unit for holding IPv6 multicast addresses used on said IPv6 network, an IP address conversion information holding unit for holding at least one of said IPv4 multicast addresses and at least one of said IPv6 multicast addresses in correspondence with each other, said IPv4 multicast addresses being held by said IP multicast membership group managing unit, said IPv6 multicast addresses being acquired from said for-conversion IP address holding unit, and an IP header converting unit for converting said IPv4 multicast address of said IPv4 packet into said IPv6 multicast address, said IPv4 packet being received by said IP transmitting/receiving unit, said IPv6 multicast address being held in correspondence with said IPv4 multicast address by said IP address conversion information holding unit.