Patent ID: 7450499

Claim:
A system for interconnecting an Internet protocol version 6 (IPv6) network and an Internet protocol version 4 (IPv4) network, comprising IP packet transmitting apparatuses transmitting IP packets between IPv6 nodes and IPv4 nodes and including: a first IP packet transmitting apparatus transmitting IP packets; and a second IP packet transmitting apparatus transmitting IP packets when the number of IP packets to be transmitted exceeds the processing capacity of the first IP packet transmitting apparatus, wherein the first and second IP packet transmitting apparatuses share processing state information of the IP packets using a predetermined message; wherein the predetermined message is an Internet control message protocol version 6 (ICMPv6) redirect message defined in a neighbor discovery protocol (NDP); wherein the ICMPv6 redirect message comprises: a flag bit that indicates the processing state of a first NAT-PT apparatus; and a target address field which stores the address of a second NAT-PT apparatus adjacent to the first NAT-PT apparatus.