Method and apparatus for interconnecting IPv4 and IPv6 networks

An NAT-PT apparatus comprising:

• a determination unit which receives an IPv6 packet and determines whether or not the received IPv6 packet is to be processed according to the current packet processing state of the NAT-PT apparatus;
• an IPv4 address pool which stores IPv4 addresses with which the address of an IPv6 node which transmitted the IPv6 packet is mapped to an IPv4 address and then used;
• a mapping table generation and storage unit which generates and stores a mapping table for mapping an IPv4 address corresponding to the address of the IPv6 node;
• and
• an IP header translation unit which translates an IPv6 packet header into an IPv4 packet header.

An NAT-PT method performed in an NAT-PT apparatus, comprising:

• (a) receiving an IPv6 packet and determining whether or not the received IPv6 packet is to be processed according to the current packet processing state of the NAT-PT apparatus;
• (b) if the determination result indicates that the NAT-PT apparatus is capable of processing the received IPv6 packet, mapping an address of an IPv6 node which transmitted the IPv6 packet into an IPv4 address by using an IPv4 address pool which stores available IPv4 addresses;
• and
• (c) translating a header of the received IPv6 packet into an IPv4 packet header.

A computer readable medium having embodied thereon a computer program for an NAT-PT processing method performed in an NAT-PT apparatus, comprising:

• (a) receiving an IPv6 packet and determining whether or not the received IPv6 packet is to be processed according to the current packet processing state of the NAT-PT apparatus;
• (b) if the determination result indicates that the NAT-PT apparatus is capable of processing the received IPv6 packet, mapping an address of an IPv6 node which transmitted the IPv6 packet into an IPv4 address by using an IPv4 address pool which stores available IPv4 addresses;
• and
• (c) translating a header of the received IPv6 packet into an IPv4 packet header.

A method of interconnecting an IPv6 network and an IPv4 network in a network comprising a plurality of IPv6 nodes, a plurality of IPv4 nodes, and at least one apparatus for transmitting IP packets between the IPv6 nodes and the IPv4 nodes, the method comprising:

• (a) receiving a DNS message for searching for an IPv4 address of a destination domain name;
• (b) transmitting the received DNS message to a DNSv4 server and receiving an IPv4 address of the destination domain name from the DNSv4 server;
• (c) allocating a predetermined prefix to the received IPv4 address to translate the IPv4 address into an IPv6 address;
• and
• (d) transmitting the translated IPv6 address to a corresponding IPv6 node.

A system for interconnecting an IPv6 network and an IPv4 network in a network including a plurality of IPv6 nodes, a plurality of IPv4 nodes, and at least one apparatus for transmitting IP packets between the IPv6 nodes and the IPv4 nodes, the system comprising:

• a DNS message receiving portion which receives a DNS message for searching for an IPv4 address of a destination domain address;
• an IPv4 address receiving portion which transmits the received DNS message to a DNSv4 server and receives an IPv4 address of the destination domain name from the DNSv4 server;
• an address translation portion which allocates a predetermined prefix to the received IPv4 address to translate the IPv4 address to an IPv6 address;
• and
• a transmitting portion which transmits the translated IPv6 address to a corresponding IPv6 node.