Soulution Of Traversaling Through NAT Investigation And Design

With the development of the internet, the available IP address reduced greatly and almost being used out. In order to solve this problem, people put forward many solutions(some of them are some long-term soulutions and others are short-term solutions), of which The solution called Network Address Translation technology got very popular and solves the IP address shortage problem effectively and provide some security protection to some extent at the same time. Yet it has shortage too. It makes some high level application such as FTP can't be used any more. As the VOIP technology became more and more popular NAT traversal is now the biggest drawback in VOIP application and should be solved in short time. There has been many solutions solving this problem and all of them has their own advantages and disadvantages and only apply to only few application scenarios.This thesis mainly analyses the existing solutions and put forward our own solution. It put emphases on discussing the feasibility of our own solution in theory,and put it into practice to veritify its' practicability.The solutions that was introduced before it is a premises and the following design and implementation of the solution is just a stimulant implementation and should be implemented in detail.This thesis aimed at proposing a solution that apply to mutilmedia transmission. The speciality of mutilmedia transmission predicate that it should base on UDP. In the first chapter we state the reason of IP address shortage and some corresponding solutions and their peculiarity. The second chapter mainly explain the NAT, its' principle and so on. The third chapter is the introduction of solutions about the NAT traversal. The forth...