信息网络理论基础第一章

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信息网络理论基础盛敏 msheng@http://www.77cn.com.cn

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References

Data Networks - Second Edition, Dimitri Bertsekas Computer Networks-Third Edition, Andrew S. Tanenbaum Broadband Integrated Networks, Mischa Schwartz Introduction to queuing theory-Second Edition, Robert, B. Cooper 清华牛志升教授的《通信网络基础》课件 先修课程《通信网络基础》、《随机过程》

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第一章概述

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1.1通信网络概述

A communication network, in its simplest form, is a set of equipment and facilities that provides a

service: the transfer of informationbetween users located at various

What is a communication network?

geographical points.

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Evolution of Network - TrafficMobile Telephone Mobile Internet 2000s, 2G/3G most people connected Voice, SMS, MMS, email, Web,……

Mobile Multimedia 2010s, 3G/4G all the people connected Voice, SMS, MMS, email, Web, TV, VoD……

1990s, 1G/2G partial people connected Voice and SMS only

2020s Mobile? wireless in everything Ubiquitous service..

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Evolution of Network - Traffic

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Evolution of Network- RateDWDM SONET OC-48 T-4 carrier

1.0E+14 Transmission rate (bits/s) 1.0E+12

The improvement in transmissionbit rate over the last 150 years. In this time we have gone from telegraph systems that operated at

1.0E+101.0E+08 1.0E+06

T-1 carrier

1.0E+041.0E+02

Baudot multiplex Printing telegraph

tens of bits/s to modern optical systems that operate at terabits/s.

1.0E+00 1850 1875 1900 1925 1950 1975 2000

1837年Morse code,数字传输系统 1851, the first submarine cable was established between London and Paris./routing, switch 1874,Baudot system, multiplex,/1876, Bell,telephone

1901,Marconi, send and receive radio signals across the Atliantic,

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Evolution of Network - Network–电信网络的发展 PSTN-》ISDN(2B+D)-》BISDN

网络模式的发展

–计算机网络的发展 LAN,WAN-》Internet

–无线通信网络的发展 AMPS-》GSM,IS_95-》IMT2000(3G)-》4G

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通信网的发展方向 未来十年网络容量提升千倍–现时4G网络可以提供最高1G下载及500M上传速度，希望5G网络可以在2020年实现。 频谱效率 *10;功率效率* 10;

信息：多媒体化交换：高速化传输：数字化

网络：综合化、智能化、个人化宽带无线网络追求的目标

传输目标：高速(100Mbps~1Gbps)高效(5~30 bps/Hz)网络目标：高用户容量、组网灵活、无缝覆盖

覆盖密度 *10–网络异构虚拟化–资源动态差异化–节点移动智能化–。。。。。。

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Evolution of Network

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1.1通信网

络的基本构成和协议

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通信网络的基本构成 物理传输链路 指在物理传输媒介(如双绞线、同轴电缆、光纤、微波传输系统、卫星传输电路等)上利用一定的传输标准(它通常规定了电气接口、调制解调的方式、数据编码的方式、比特同步、帧格式和复分接的方式等)形成的传输规定速率(和格式)的数据比特通道。

网络节点

用户终端(电话机、传真机、计算机),路由器、程控交换机

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通信网络的协议体系

What is the communication protocol?– a communications protocol is the set of standard rules for data representation, signaling, authenticationand error detection required to send information over a communication channel.

在计算机网络中，为了使计算机或终端之间能够正确地传递信息，必须有一整套关于信息传输顺序、信息格式和信息内容等的约定，这一整套约定称为通信协议。

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通信网络的协议体系

A protocol is a set of rules that governs how two ormore communicating parties are to interact. When dealing with networks we run into a multiplicity of protocols, such as HTTP, FTP, and TCP. The purpose of a protocol is to provide some type of communication service.

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通信网络的协议体系1. The user prepares an e-mail message that includes the recipient’s e-mail address, a subject line, and a body.

Example:SMTP and E-mail Here a mail client application interacts with a local SMTP server to initiate the delivery of an e-mail message.

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通信网络的协议体系

Example:SMTP and E-mail Here a mail client application interacts with a local SMTP server to initiate the delivery of an e-mail message.

2. When the user clicks send, the mail application prepares a file with the above information and additional information specifying format (plain ASCII to encode non-ASCII information )