中文摘要：

为缓解IPv4模式下的IP地址短缺问题，文中以Linux为系统平台，深入分析了网络地址转换（NAT）的基本原理和实现技术，然后对其扩展应用进行了理论和实际的探讨，最后将排队模型引入到NAT的映射过程中，并进行了相应理论分析。给出了一种NAT的形式化模型和关于NAT映射的函数，实现了一种基于端口映射方式的具体算法。研究结果表明，网络地址转换为解决IP地址短缺提供了有效的解决方案，但其应用并非仪限于此。网络地址转换技术可广泛适用于虚拟服务器、负载均衡以及多路传送等多种不同应用领域。

英文摘要：

To remit the shortage of IP address under IPv4 mode, using Linux as the platform, it firstly introduces the basic theory and classic techniques of NAT. Then it puts emphasis on its expand techniques in theory and in practice, and a queuing model is introduced to NAT mapping process. The related theory is analyzed in the end. An NAT formal models and an NAT mapping functions are given, as well as a specific algorithm about the way realization based on port mapping. Research results show that NAT technology provides an effective solution to solve the shortage of IP address, but its application is not only that. It can be widely used for many different applications such as virtual server, load balancing, multi-channel transmission ,etc.