论文总字数：18437字

摘 要

计算机网络经历了几十年的发展，在人们的生产、生活中占有越来越重要的地位。作为计算机网络主要协议的IPv4已经十分成熟，成为计算机网络的基石。但是由于自身的限制，己经逐渐暴露了许多问题和缺点，于是IPv6被IETF设计出来用以替代IPv4。

Internet在我国的发展也己10多年，网络规模已相当可观，要将一个商用网由IPv4改造为IPv6是存在一定难度的。但是IPv4地址的严重短缺问题在严重地威胁着我们，特别是严重影响IP网的持续发展。我国的人口基数甚大，经济增长的势头良好，固定通信网的规模和移动通信网的规模己居世界第二位。IPv4已无法满足我国高速发展的需求。整个网络从IPv4过渡到IPv6需要比较长的时间，所以两种网络将在今后长期共存。中国教育与科研计算机网络（CERNET）也将面临这种情况，所以研究基于校园网的IPv4向 IPv6的平滑过渡技术是十分必要且有前景的。

本论文将介绍IPv6的原理，并对IPv6协议和IPv4协议进行比较，分析几种常见过渡技术：双栈技术、隧道技术、NAT-PT协议转换。结合目前大多数校园网的网络部署情况，将这些过渡技术合理的运用于其中，实现在当前以IPv4为主的网络中兼容IPv6网络。以期在今后将来很长的一段时间内做到在校园网IPv4网络和IPv6网络互联、互通、互相能够访问。

关键字：IPv6；平滑过渡；双栈技术；Tunnel技术；NAT-PT技术

ABSTRACT

The computer networks，especially the rapid development of Internet bring lots of values for society today and it almost has covered all kinds of fields. But the main Protocol of Internet,IPv4 has not satisfied the need of the development in future because it has been limited by the defects in present system,IPv6 was devised to substitute IPv4 by IETF.

Internet is close to also already 10 in development of our country, the network scale is already pretty considerable, needs to reform a commercial net from IPv4 for IPv6 is also difficult.But grave IPv4 address shortage problem is threatening us in grave field sustained development affecting the IP net’s especially gravely. Population base of our country is very big, the economic growth tendency is fine, and the scale fixing telecommunication network sand the scale moving telecommunication networks already occupy second worlds.IPv4 has no way to satisfy the need that our country high speed develops. The entire transition from IPv4 to IPv6 will spend much time, and the coexistence will last for a long period of time, Campus network is also confronted with the same question.In this situation, the research on the smooth transition from IPv4 to IPv6 is of necessity and prospect.

In the thesis, we compare IPv4 with IPv6, introduce the fundament characteristics of IPv6, and analyze some varieties of familiar transition technique: tunnel technique, Dual stack and NAT-PT Network Address Translation Protocol Translation.Combined with the campus network dispose, these transition techniques are operated reasonably, to apply the IPv6 compatibly in current IPv4 network.In the future, the users could connect and visit mutually between IPv4 and IPv6.

Key words: IPv6; smooth transition; Dual stack; tunnel technique; NAT-PT

目录

第一章绪论 1

1.1 引言 1

1.2课题背景 2

1.3课题意义 3

1.4 本文研究内容 4

1.5 本文工作安排 5

第二章IPv6网络协议的研究 6

2.1IPv4的不足之处 6

2.2 IPv6协议的产生 7

2.3 IPv6技术 8

第三章IPv6的过渡技术 20

3.1三种主要过渡技术 20

3.2三种过渡方案的对比研究 23

第四章校园网过渡技术设计与实现 25

4.1实验平台的选择 25

4.2Tunnel技术实现 27

第五章总结与展望 34

5.1总结 34

5.2展望 34

致谢 37

参考文献 38

附录 39

第一章绪论

1.1 引言

人们于上世纪初期就开始担忧IPv4地址可能用尽的问题,相关专家预测表示,若IPv4的地址分配按目前的速率增长,若干年后地址空间将会被耗尽。为了解决这一问题，人们提出了一个全新的地址版本,称为IPv6。但是一种新的协议需要长时间的发展,在此过程中需要一种短期方案来解决地址耗尽问题。

人们将这种短期的解决方法称之为网络地址转换（NAT），NAT支持多个主机共用一个或者多个公有地址。NAT的出现有效的减缓了IPv4地址被用尽的问题，因此在网络的搭建中频繁使用。

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