Study On IPv4/IPv6 Translation Gateway

With the rapid development of Internet,the limitation of IPv4 ,the kernel protocol of current internetworking, appears gradually,it already encumbrances the development of Internet.The next generation network protocol IPv6 has naissanced for solving the limitation of IPv4,it not only solves the question that IPv4 appears but also has some new features and supports for the future application well.Compared with IPv4,IPv6 has more advantages,it is necessary to replace IPv4 with IPv6.But it is impossible that all devices upgrade to IPv6 in the same time,moreover, it is not necessary,the internet transition from IPv4 to IPv6 will take rather a long time.The IPv4 network have developed for tens of years,its network spreads all over the world and its resources is abundant very much,but the resources of IPv6 is scarce,if we can implement the interoperation between IPv4 and IPv6 network and the host in the IPv6 network can access the resources of IPv4 network,IPv6 had more attraction to the user and will reduce the cost of upgrade and will accelerate the spread and popularization.The study of IPv4/IPv6 translation gateway is necessary for implementing interoperation of IPv4/IPv6.The translation gateway brought forward by this article is composed of three module:1)the capture module of packet in the windows,2)the address manager and translation module of packet,3)the protocol translation module of packet.The capture of packet is implementated by the NDIS driver program.The translation gateway,between the protocol drivers and the NIC drivers,can capture all packet and deal with it based on the demand of gateway rightly,then forward it.The address translation module implements three mode translations:1)static address translation,2)dynamic address translation,3)port/address translation.the protocol translation implements the algorithm of IP header between IPv4 and IPv6,between ICMPv4 and ICMPv6 and the upate of checksum field of TCP/UDP. In the end,We implemented translation gateway by VC++6.0 and Windows DDK,meanwhile, examined Latency of traslating packet,Bandwidth of network and the operation of familiar application.The gateway passed these examinations successfully.It realizes requirement of a middle or small network for traslation gateway.Therefor,it is a successful mechanism of IPv4/IPv6 translation gateway and is worthy to be popularized.