Lecture6 计算机网络

1、LectureLecture6 6 计算机网络哈尔滨师范大学，软件学院，软件工程教研室2022-1-81软件学院软件工程教研室2022-1-8软件学院软件工程教研室1网络基础知识l21世纪的特征l数字化l网络化l信息化l三网合并l电信网络l有线电视网络l计算机网络l计算机网络向用户提供的功能l在线通信l资源共享2022-1-8软件学院软件工程教研室2计算机网络的发展l从单个网络ARPANET向互联网发展（1969）l主干、地区、校园（企业）三级结构的因特网（1985）l多层次ISP结构的因特网（1994）2022-1-8软件学院软件工程教研室3Communication SystemslEle

2、ctronic systems that transmit and receive informationlBasic elementslSending/Receiving devicelCommunication channellConnection deviceslData transmission specificationsCommunication Channels lEssential element of communication systemlTwo categorieslPhysical connection lWireless connectionWired Connec

3、tionslTelephone lineslTwisted pairlOld standard Coaxial cable Single solid-copper core 80 times faster Fiber-optic cable Light through glass 26,000 times fasterWireless ConnectionslMicrowavelHigh-frequency radio waveslLine-of-sight communicationlRelayedlSatellitelMicrowave relay stationslGeostationa

4、rylLarge volume of dataConnection Devicesl Modulator-demodulatorlConverts analog signal to digital signall Speed in bits per second (bps)l Externall Internall PC Card l WirelessConnection TypeslDial-up servicelMost popular, but slowlDigital subscriber line (DSL)lUses existing phone lines, fastlCable

5、lExisting television cableslSatellite/air connection serviceslSlower than DSL, but faster than dial-upData TransmissionlBandwidthlHow much information can be transmitted at one timelProtocollSpecific rules guiding the exchange of information2022年1月8日BandwidthlMeasurement of capacity of the communica

6、tion channellCategorieslVoicebandlStandard phone line, dial-uplMedium bandlSpecial leased lineslBroadbandlHigh capacity transmissionslDSL, cable, satelliteData Transmission Direction lSimplexlOne direction onlylHalf-duplexlOne direction at a timelFull-duplex lBoth direction simultaneously网络体系结构l通信协议

7、l从一个网络节点向另一个网络节点有效地传输数据的一套规则l计算机网络的各层及其协议的集合，称为网络的体系结构lOSI体系结构：物理层、数据链路层、网络层、传输层、会话层、表示层、应用层lTCP/IP体系结构：网络接口层、网络层、传输层、应用l五层协议体系结构：物理层、数据链路层、网络层、传输层、应用层2022-1-8软件学院软件工程教研室13ProtocolslSet of communication rules for exchange of informationlTransmission control protocol/Internet protocol (TCP/IP)lIdenti

8、ficationlIP AddresslDomain name system (DNS)lReformattinglReassemble packetsl网络如何通信（信封实例）网络如何通信（信封实例）NetworkslTwo or more connected computers that share information and resourcesl NodelDevice connected to a networklClientlNode that requests and uses resources available from other nodeslServer lNode

9、that shares resources with other nodes More Network TermslNetwork operating system (NOS) lSoftware to control and coordinate activities between nodes on a networklDistributed processinglComputing power located and shared at different locationslHost computerlLarge centralized computer, usually a main

10、frame Network ArchitecturelArrangement of network communication channellCoordinates and shares resourceslTopologylStar networklBus networklRing networklHierarchicalStar NetworkBus NetworkRing NetworkHierarchical NetworkStrategieslWays to coordinate sharing of resourceslMost commonlTerminal network s

11、ystemlPeer-to-peer network systemlClient/Server network system网络分类网络分类l按照大小和地理范围按照大小和地理范围l个人区域网个人区域网PANl局域网局域网LANl城域网城域网MANl广域网广域网WANLocal Area NetworkslComputers and devices linked in close proximity to each other lTypically use a bus form of organizationlNetwork gatewayslNetwork bridgeMetropolitan

12、 Area NetworkslLink nodes and resources within the geographical bounds of a citylLink between buildingslCellular phones can extend the reach of a MANWide Area NetworkslCountrywide and worldwide networklUse microwave relays and satelliteslInternet lWidest of all WANEThernet以太网l目前最流行的局域网l最重要的协议CSMA/CD

13、l以太网的设备lX端口以太网集线器或以太网交换机l两台以上上网设备lUTP、RJ-45若干l安装步骤l电源的设置l设计电缆走线，铺设电缆l安装集线器或交换机，连接线缆l配置各工作站（计算机）2022-1-8软件学院软件工程教研室27WLAN简介l基本结构2022-1-8软件学院软件工程教研室28WLAN简介l无线集中控制网络l寝室中如何组建l安装路由器l将路由器与PC相连l设置路由器l安装无线工作站l连接因特网2022-1-8软件学院软件工程教研室29WLAN简介l无线点对点网络2022-1-8软件学院软件工程教研室30WLAN简介2022-1-8软件学院软件工程教研室31WLAN简介l实用小

14、技巧l用笔记本提供热点服务lnetsh wlan set hostednetwork mode=allow ssid=testnet key=test1234lMode=allow：承载网络模式设置为开始lSsid=testnet：无线网络广播名称为testnetlKey=test123：无线网络的加入密码l用智能手机提供热点服务l先将手机连入网络l进入手机设置-wlan-网络共享与便携式热点2022-1-8软件学院软件工程教研室32使用局域网l对等网l文件共享，映射网络驱动器l共享打印机l基于域的网络l用户认证l文件服务器lftp服务lIIS服务l2022-1-8软件学院软件工程教研室33I

15、nternet的服务l实时消息lVoIPl网格计算lFTPlWEB，URL，HTMLl电子邮件l在线购物l搜索引擎2022-1-8软件学院软件工程教研室34Organizational Internets: Intranet and Extranets lIntranetslA private network within an organization that resembles the Internet.lExtranetslA private network that connects more than one organization.lFirewallslA security system designed to protect an organizations network against external threats.IOTlSee the webpage2022-1-8软件学院软件工程教研室36作业1.30台PC+1台Server，请给出一个组网方案，并给出预算，要求图文并茂。该网络主要用于学校日常教学，请考虑必备软、硬件，方便教师和学生的使用。2.写一份关于google搜索引擎