| With the rapid development of Internet, it has been an important subject in the study of Internet area, that how to get the transition from the network based on IPv4 to the next generation network based on IPv6. NAT-PT which has been one of the widely used transition techniques can achieve the connection between IPv4 nodes and IPv6 nodes, through the address translation and the protocol translation of packets.The dissertation discusses three existing transition techniques including dual IP stack, tunneling and NAT-PT, and gives a detailed introduction to the NAT-PT technique. It also analyzes the principle and process of every module in translation gateway based on NAT-PT. It will allot more resources of system in protocol translation module of traditionary translation gateway that probably gives rise to network block when processing messages in large quantities sent by several computers in larger network at the same time, and becomes the bottleneck of the communication between IPv4 and IPv6 network.The dissertation brings forward the scheme of IPv4/IPv6 translation gateway based on Linux with several PT modules by means of separating PT module from NAT module and DNS-ALG. Several PT servers are placed in both IPv4 and IPv6 network. Several computers establish the conversations at the same time. The packets of all conversations will be processed by different PT servers according to the corresponding rules, after address mapped by only NAT server. All PT servers work together to divide up the processing task, which will increase the processing speed of the whole translation gateway system. The characteristics of IPv4/IPv6 translation gateway with several PT modules are parallel,quick and stable.The realization of whole architecture is based on Netfilter framework on Linux system. The experiment leads up to the fact that the improved translation gateway runs faster than the traditional translation gateway in messages processing, which achieves the expectant effect. |
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