The Research Of Changchun Unicom IP Network IPv4/v6 Coexistence And Transition Plan

Compared with IPv4, IPv6 protocol has many new features. For instance, the new message structure is more simplified and flexible, huge address space, efficient hierarchical addressing and routing structure as well as the internal security ,a better support for QoS, good expansibility, built-in mobility and new neighbor discovery protocol, etc. From the operator's point of view, there are mainly two quite attractive characteristics: firstly, the IPv6 has huge address space, in which the 128 bit address format is used. In the circumstances of rational allocation, it can meet the needs of all current access addresses and applications addresses; secondly, the package of IPv6 is more simplified than that of IPv4. It improves the router's forwarding rate and realizes the efficient routing. The checksum is not included in the encapsulation and there are less endpoints treatment. There is a decrease of utilization in the same subnet equipment without using broadcast. The built-in QoS reduces the processing pressure in the intermediate network equipment . Facing the shortage of IPv4 address resource and considering about the large amounts of advantages of the IPv6 , it is really necessary and imperative for the transition from IPv4 to IPv6 done by the operator.In this paper, the present situation of the development of IPv6 technology at home and abroad is introduced. The essay has a further study on the theory of IPv6 protocol and the IPv6 addressing principle, IPv6 header structure and ICMPv6 technology and IPv6 routing technology are to be discussed in detail as well. In the aspect of transition mechanism, several commonly used IPv6 transition technologies have been selected for researching, including dual stack technology, tunnel technology, translation technology, and a comparison between them . Then combining the Unicom IP network deployment and existing network business operation, selecting different transition technologies to apply to different transition periods as for rational use. In the experimental environment, the IP bearer network in the early days of IPv6, IPv4 and IPv6 coexist period and the end of the whole IPv6 network as well as the equipment deployment and route planning have been realized. Theoretical basis and practical basis have been provided for the smooth transition from the IPv4 to IPv6 network in China Unicom IP network for the future.