The Research And Implementation Of Load Balance Of NAT-PT Cluster

Because IPv4 has some defects in address space, security, automatic address configuration and so on, the technology of IPv6 appears. And it is obviously that IPv6 will take the place of IPv4, for IPv6 has extended address space, introduced a brand-new IP address assignment,supported QoS and stream media, perfected security mechanism and equipped with some other new characteristics. But, at present the Internet"ocean"that runs IPv4 can't be substitute by that of running IPv6 at once. It is a gradual complex systematic project .Two problems here should be solved. One is the communication from the pure IPv4 host to the pure IPv6 host and the other is the communication from the pure IPv6 host to the pure IPv4 host. To solve the problem, normally there are three ways: dual stack mechanism, tunnel mechanism, and transition mechanism. The transitional program of translation gateway based on the NAT-PT (network address translation-protocol translation) can ensure that the pure IPv6 host or pure IPv4 host can communicate with other host (IPv6 host or IPv4 host) freely and the communication can initiate from any host inside the net arbitrarily. In virtue of adoption of translation gateway program, what the ISP need to do is just some correlative work to IPv6 while the translation gateway will guarantee the service and function of the host against interference, thus the difficulty of upgrade recedes greatly.The NAT-PT becomes the key node of inter-domain visits within IPv4 network and IPv6 network visiting each other. To improve reliability and stability of the key node, this paper contributes to researching load balance technique of NAT-PT cluster, designing and realizing the prototype system. Major achievements in this paper are as follows.1. It analyzes the work characteristics, presents some load balance projects to solve the congestion of NAT-PT, then selects the centralized load balance project among them, and designs the entire structure of load balance of the NAT-PT cluster.2. It shows the structure model of the software for the centralized load balance project, which is composed of three layers, system parameter selection layer, parameter calculation and mapping layer, and load location tactics layer.3. It elaborates on the setup and parameter selection of system performance, and provides extended weighted round robin algorithm of dynamic load balance.