| After its birth more than 30 years ago, Internet, being the fastest way of finding useful information, has played a huge impact on human society and people's life in this economic information society. Since the first version of the internet communication Protocols IPv4 actually used more than 30 years ago, processor performance, the typical memory size and the Internet backbone link bandwidth has increased from 1000 to several millions times. Also the application mode and people using it has change greatly. But it has not changed ever since. With the increasing demand for diversification, for example, the new mobile communications and real-time interactive multimedia communications, IPv4 will ultimately transit to IPv6 due to many of its problems, such as lack of address space, poor quality of services, complex configuration, poor mobility support and security. To resolve these problems, countries, organizations, operators and experts all over the world have had abroad study of the next general internet protocols. That is IPv6. IPv6, comparing to IPv4, has many new features, the simplified IP header format, host address auto-configuration, authentication and encryption, and strong mobility support and so on.This paper, from the structure view of IPv6, first introduces on the basic knowledge about IPv6, carrying out a detailed comparison of the header format between IPv6 and IPv4 and making an analysis of the neighbor discovery protocol with "plug and play" features and the RIPng Routing Protocol. Then the paper introduces the basic concept of mobile IPv6, analyses its working mechanism, characteristics and prospects, then study on the key technology, handover technology, also the paper studies the optimizing security of MIPv6. Networks transition of IPv4 to IPv6 will be a huge and complex project. The paper analyses the IPv6/IPv4 double protocol stack technology, NAI-PT network address/protocol conversion technology and especially the tunnel technology. This paper researches on the most commonly used manual configuration tunnel, automatic allocation tunnel, 6 over 4, 6 to 4, ISATA, and so on. At last the paper introduces the prospect of IPv6. |
