Patent ID: 7583698

Claim:
A communication control apparatus which is coupled to a network, and includes a protocol control module for generating an Internet Protocol version 4 (IPv4) packet, a header conversion module for translating the IPv4 packet into an Internet Protocol version 6 (IPv6) packet, and a network control module for transmitting the IPv6 packet to the network and receiving a packet from the network, wherein the apparatus further comprises: a translation control module for translating an Internet Group Management Protocol (IGMP) header of an IGMP packet into a Multicast Listener Discovery (MLD) header of an MLD packet to generate the MLD packet by converting at least type information contained in the IGMP header of the IGMP packet into type information in the MLD header of the MLD packet, and by converting an IPv4 multicast address contained in the IGMP header of the IGMP packet into an IPv6 multicast address, or translating an MLD header of an MLD packet received from the network into an IGMP header of an IGMP packet to generate the IGMP packet by converting at least type information contained in the MLD header of the MLD packet thus received into type information in the IGMP header of the IGMP packet, and by converting an IPv6 multicast address contained in the MLD header into an IPv4 multicast address; and a switch control module for determining that a packet generated by the protocol control module is an IGMP packet by a fact that the packet thus generated contains an IGMP header, or for determining that a packet received from the network is an MLD packet by a fact that the packet thus received contains an MLD header, thereby to deliver the packet thus determined to the translation control module, wherein the translation control module terminates translation process, if the type information of the IGMP header indicates “Membership Query”.