Research On Techniques Of Design And Lmplementation Of The NAT-PT Gateway

Deficiencies of IPv4 protocol in address space, header processing, and in handling stream-oriented traffic, have spurred the development of IPv6. In view that migration from IPv4 to IPv6 will take quite a long time, it is very important to interconnect systems of supporting different versions of IP.During the migration period, people have to face with two types of interconnection problems, i.e, interconnection among systems supporting the same version of IP via another version of IP networks, and that between systems supporting different versions. In the former case, encapsulating, tunneling, or ferrying would be the best choice; while in the latter case, there is a need for protocol conversion. For this purpose, IETF has recommended a technique called NAT-PT (Network Address Translation - Protocol Translation), which is the main topic of this dissertation.The Sichuan Net-corn Key Laboratory has been working on IPv6 testing techniques; therefore, the work presented in this dissertation aims at a prototype NAT-PT gateway, which can be used as one of testing targets. In view that there are not many NAT-PT products around, research and development of a NAT-PT gateway are necessary both for technical exploration and for future implementation. The author's prototype NAT-PT gateway was developed in the Linux OS environment within a PC for security reason and for productization.The work presented in this dissertation consists of four aspects: understanding and analysis of NAT-PT, analysis of tactics and architecture of implementation of NAT-PT gateway, design and programming, and system debugging and testing of the gateway. IPV4address-pool is one of the main features of author's gatway, which simplifies the system configuration for system manager. Finally, the author has put forward a new thinking to combine the NAT-PT with the Encapsulation technique, which might contribute flexibility and adaption ability to NAT-PT.The work presented in the dissertation spans the whole process in software engineering, from requirement analysis through system analysis and design, programming, debugging, and testing. Preliminary testing has shown that the design purpose has been fulfilled and the prototype gateway is operational. A thorough testing including conformance test and performance test were planned at the begging; however, for the reason that the testing system at the laboratory has not yet been completed during this development, a more convincing testing has to be regretly left behind.