本书系统全面地介绍了通信网络的机械原理、开发及应用等多方面的知识。本书内容丰富全面、实用性强，是一本学习通信网络基础的首选参考书。

Preface xi

Chapter 1 Introduction to Communication Networks

Chapter 2 The Way Networks Work

Chapter 3 Internet

Chapter 4 Local Area Networks

Chapter 5 Asynchronous Transfer Mode

Chapter 6 Data Link Layer and Retransmission Protocols

Chapter 7 Physical Layer

Chapter 8 Security and Compression

Chapter 9 Performance Evaluation and Monitoring

Appendix A Probability

Appendix B Queues and Metworks of Queues

Appendix C Communication Principles

Appendix D References

A network comsists of links,routers kr switches,and computers.The user com-puters and seervers are called end systems or hosts.The routers are transfer systems.In this section,we take a quick look at these basic components and summarize their characteristics.