IPV6 TO IPV4 隧道.pdfVIP

Technology Introduction IP Services Tunneling Tunneling Introduction to Tunneling The expansion of Internet results in scarce IPv4 addresses. Although the technologies such as temporary IPv4 address allocation and Network Address Translation (NAT) relieve the problem of IPv4 address shortage to some extent, they not only increase the overhead in address resolution and processing, but also lead to high-level application failures. Furthermore, they will still face the problem that IPv4 addresses will eventually be used up. Internet Protocol Version 6 (IPv6) adopting the 128-bit addressing scheme completely solves the above problem. Since significant improvements have been made in address space, security, network management, mobility, and QoS, IPv6 becomes one of the core standards for the next generation Internet protocol. IPv6 is compatible with all protocols except IPv4 in the TCP/IP suite. Therefore, IPv6 can completely take the place of IPv4. Before IPv6 becomes the dominant protocol, the network using the IPv6 protocol stack is expected to communicate with the Internet using IPv4. Therefore, an IPv6-IPv4 interworking technology must be developed to ensure the smooth transition from IPv4 to IPv6. In addition, the interworking technology should provide efficient, seamless information transfer. The Internet Engineering Task Force (IETF) set up the next generation transition (NGTRANS) working group to study problems about IPv4-to-IPv6 transition and efficient, seamless IPv4-IPv6