第06章 通信与网络

通讯网络的组成“Anyoneintheworldcouldbeyourcustomer;anyoneintheworldcouldbeyourcompetitor.”网络模型NetworkModel:Acommunicationnetworkisanyarrangementwhereasendertransmitsamessagetoareceiveroverachannelconsistingofsometypeofmedium,第6章通信与网络,图6.1以单计算机为中心的远程联机系统,图6.2存储转发的计算机网络,图6.4某人寿保险公司的局域网和广域网,图6.5点到点式网络的拓扑结构,图6.6广播式网络拓扑结构,图6.7同轴电缆结构图,图6.8光纤传输,1,2,3,4,5,EnduserTele-Tele-Tele-computerprocessorsChannelsprocessorsAbuilding;Amanufacturingplant.,Pcworkstation,Workgroupdatabase,Sharedprinter,NetworkServer,SharedHardDiskUnit,Gatewaytoothernetwork,WANsWideAreaNetworks一个城市,或更大区域,国家,甚至全球.,Satellite,EarthStation,SatelliteCentraloffice,HostComputer,Multiplexer,Hubber,Coaxialcable,Modem,SatelliteRegionalOffice,WirelessLan,Gateway,Enduser,Hubber总线器Gateway连接两个协议(Protocal)可不一样的网Router选路功能,上五层一样Bridge连接两个相同的网,应用层,表达层,开启层,传送层,网络层,数据链层,物理层,INTERNET因特网、互联网、网际网,NIINationalInformationInfrastructureClinton1993“NII行动计划”将各种物理器件连接集成成完善的网络.用以彻底改变人们的生活,工作,和交往方式.TVondemandShoppingindemandLearningondemandCNIIChinaNationalInformationInfrastructure,1.金桥工程2.金卡工程3.金关工程4.金智工程5.金税工程6.金卫工程7.金农工程8.金通工程9.金企工程10.金图工程,Internet,IntranetNooneownsit,NooneknowsitOnlycommonprotocol,TCP/IPCommoninterfacetechnologySeeLaudonsection9.1,Cando:E-mailUsenetNewsgroupLISTSERVs,ChattingTelnetFiletransferProtocol,FTPGopherWorldWideWebhypertext,IP地址:上海长途电信局33域名(DomainName)上海交大图书馆,NetworkinginChinaChinaEducation&ResearchNetwork(CERNET)ChinaMPTNetwork(ChinaNET)ChinaAcademyofSciencesNetwork(CASNET)ChinaGoldenBridgeNet(ChinaGBN),图6.15对称密钥系统,图6.16公钥和私钥加密系统,图6.18数字签名交易方式,图6.19建立SSL会话示意,图6.20三