C語(yǔ)言雙語(yǔ)課件 CHAPTER2

計(jì)算機(jī)網(wǎng)絡(luò)與通信

DataandComputerCommunications2.

協(xié)議體系結(jié)構(gòu),TCP/IP,互聯(lián)網(wǎng)應(yīng)用ProtocolArchitecture,TCP/IP,andInternet-BasedApplications

為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的三層協(xié)議體系

TCP/IP協(xié)議體系結(jié)構(gòu)

多媒體1ProtocolArchitecture,TCP/IP,andInternet-BasedApplicationsTodestroycommunicationcompletely,theremustbenorulesincommonbetweentransmitterandreceiver—neitherofalphabetnorofsyntax

—OnHumanCommunication,ColinCherry2Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體32.1TheNeedForProtocolArchitectureTotransferdataseveraltasksmustbeperformed:1.)thesourcemustactivatecommunicationspathorinformnetworkofdestination2.)thesourcemustmakesurethatdestinationispreparedtoreceivedata3.)thefiletransferapplicationonsourcemustconfirmfilemanagementprogramatdestinationispreparedtoacceptandstorefile4.)aformattranslationfunctionmayneedtobeperformediftheformatsonsystemsaredifferent4FunctionsofProtocolArchitecturebreakslogicintosubtaskmoduleswhichareimplementedseparatelymodulesarearrangedinaverticalstackeachlayerinthestackperformsasubsetoffunctionsreliesonnextlowerlayerforprimitivefunctionschangesinonelayershouldnotrequirechangesinotherlayers5KeyFeaturesofaProtocolAprotocolisasetofrulesorconventionsthatallowpeerlayerstocommunicate.Thekeyfeaturesofaprotocolare:SyntaxformatofdatablocksSemanticscontrolinformationforcoordinationanderrorhandlingTimingspeedmatchingandsequencing語(yǔ)法語(yǔ)義時(shí)序關(guān)系6Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體72.2ASimpleProtocolagentsinvolved:applicationscomputersnetworksexamplesofapplicationsincludefiletransferandelectronicmailtheseexecuteoncomputersthatsupportmultiplesimultaneousapplications8CommunicationLayerscommunicationtasksareorganizedintothreerelativelyindependentlayers: ApplicationlayerContainslogictosupportapplicationsTransportlayerprovidesreliabledatatransferNetworkaccesslayerconcernedwiththeexchangeofdata（應(yīng)用層）（傳輸層）(網(wǎng)絡(luò)接入層)9NetworkAccessLayer網(wǎng)絡(luò)接入層coverstheexchangeofdatabetweenanendsystemandthenetworkthatitisattachedtoconcernedwithissueslike:destinationaddressprovisioninvokingspecificserviceslikepriorityaccessto&routingdataacrossanetworkfortwoendsystemsattachedtothesamenetwork10TransportLayer傳輸層11ApplicationLayer應(yīng)用層containsthelogicneededtosupportuserapplicationsseparatemoduleisneededforeachtypeofapplication12ProtocolArchitectureandNetworks13ProtocolsinaSimplifiedArchitecture14Addressing尋址Twolevelsofaddressingareneeded:eachcomputeronthenetworkhasauniquenetworkaddresseachapplicationhasanaddressthatisuniquewiththatcomputer(SAPs)15ProtocolDataUnit(PDU)

協(xié)議數(shù)據(jù)單元thecombinationofdataandcontrolinformationisaprotocoldataunit(PDU)typicallycontrolinformationiscontainedinaPDUheadercontrolinformationisusedbythepeertransportprotocolatcomputerBheadersmayinclude:sourceport,destinationport,sequencenumber,anderror-detectioncode16NetworkAccessProtocolafterreceivingsegmentfromtransportlayer,thenetworkaccessprotocolmustrequesttransmissionoverthenetworkthenetworkaccessprotocolcreatesanetworkaccessPDU(packet)withcontrolinformationheaderincludes:sourcecomputeraddressdestinationcomputeraddressfacilitiesrequests17Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體18TCP/IPProtocolArchitectureResultofprotocolresearchanddevelopmentconductedonARPANETReferredtoasTCP/IPprotocolsuiteTCP/IPcomprisesalargecollectionofprotocolsthatareInternetstandards19TCP/IPLayersandExampleProtocols20PhysicalLayercoversthephysicalinterfacebetweencomputerandnetworkconcernedwithissueslike:characteristicsoftransmissionmediumnatureofthesignalsdatarates21NetworkAccessLayercoverstheexchangeofdatabetweenanendsystemandthenetworkthatitisattachedtoconcernedwithissueslike:destinationaddressprovisioninvokingspecificserviceslikepriorityaccessto&routingdataacrossanetworkfortwoendsystemsattachedtothesamenetwork22InternetLayerimplementsproceduresneededtoallowdatatotravelacrossmultipleinterconnectednetworksusestheInternetProtocol(IP)toprovideroutingfunctionimplementedinendsystemsandrouters23Host-to-Host(Transport)LayerconcernedwithprovidingreliabledeliveryofdatacommonlayersharedbyallapplicationsmostcommonlyusedprotocolistheTransmissionControlProtocol(TCP)24OperationofTCP/IP25TCP/IPAddressRequirementsTwolevelsofaddressingareneeded:eachhostonasubnetworkmusthaveauniqueglobalinternetaddresseachprocesswithahostmusthaveanaddress(knownasaport)thatisuniquewithinthehostIPaddressPortnumber26OperationofTCP/IP27TransmissionControlProtocol(TCP)TCPisthetransportlayerprotocolformostapplicationsTCPprovidesareliableconnectionfortransferofdatabetweenapplicationsATCPsegmentisthebasicprotocolunitTCPtrackssegmentsbetweenentitiesfordurationofeachconnection28TCPHeader29UserDatagramProtocol

(UDP)alternativetoTCPdoesnotguaranteedelivery,preservationofsequence,orprotectionagainstduplicationaddsportaddressingcapabilitytoIPusedwithSimpleNetworkManagementProtocol(SNMP)30UDPHeader31IPHeader32IPv6ProvidesenhancementsoverexistingIPDesignedtoaccommodatehigherspeedsandthemixofgraphicandvideodataDrivingforcewastheneedformoreaddressesduetogrowthoftheInternetIPv6includes128-bitsourceanddestinationaddressfields33IPv6Header34SomeTCP/IPProtocols35思考題協(xié)議是什么？為什么需要協(xié)議？協(xié)議構(gòu)成的基本要素是什么？協(xié)議體系結(jié)構(gòu)為什么采用分層的方法？?jī)?yōu)缺點(diǎn)？三層簡(jiǎn)單協(xié)議體系結(jié)構(gòu)中，各層協(xié)議完成的功能？網(wǎng)絡(luò)系統(tǒng)中的兩級(jí)地址是？靠什么來(lái)傳遞對(duì)等層協(xié)議相關(guān)信息？協(xié)議體系結(jié)構(gòu)的工作？TCP/IP協(xié)議包括哪五個(gè)部分？36Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體37協(xié)議分層的理解請(qǐng)舉一日常生活中的例子來(lái)形象地描述該模型中各層的peer-to-peerprotocol（對(duì)等協(xié)議）和上下層之間的interface（接口）。北大學(xué)生張明給理工大學(xué)生李強(qiáng)寫(xiě)信的例子

張明寫(xiě)信李強(qiáng)讀信

封入信封拆開(kāi)信封投入信箱從信箱中取信件收信分檢裝郵包開(kāi)郵包選路投遞郵包送轉(zhuǎn)運(yùn)站從轉(zhuǎn)運(yùn)站取回郵包裝列車箱發(fā)運(yùn)列車箱卸包送轉(zhuǎn)運(yùn)站中文姓名地址目的地址目的站38張明給李強(qiáng)寫(xiě)信的通信協(xié)議體系結(jié)構(gòu)圖例張明（發(fā)送方）李強(qiáng)（接收方）2/1接口3/2接口4/3接口第4層第3層第2層第1層第2層對(duì)等協(xié)議第1層對(duì)等協(xié)議第3層對(duì)等協(xié)議第4層對(duì)等協(xié)議寫(xiě)信讀信封信投信收信分檢裝包轉(zhuǎn)運(yùn)郵包裝車卸車取回郵包投遞選路拆包拆信取信發(fā)車到站鐵軌（傳輸媒體）392.4StandardizedProtocolArchitectures40LayerSpecificStandards

特定層的標(biāo)準(zhǔn)41OSIStandardizationframeworkforstandardizationwasmotivatorlowerlayersareconcernedwithgreaterlevelsofdetailseachlayerprovidesservicestothenexthigherlayerthreekeyelements:ProtocolspecificationServicedefinitionAddressing42PrimitiveTypesREQUEST請(qǐng)求AprimitiveissuedbyaserviceusertoinvokesomeserviceandtopasstheparametersneededtospecifyfullytherequestedserviceINDICATION指示Aprimitiveissuedbyaserviceprovidereitherto:indicatethataprocedurehasbeeninvokedbythepeerserviceuserontheconnectionandtoprovidetheassociatedparameters,ornotifytheserviceuserofaprovider-initiatedactionRESPONSE

響應(yīng)AprimitiveissuedbyaserviceusertoacknowledgeorcompletesomeprocedurepreviouslyinvokedbyanindicationtothatuserCONFIRM

證實(shí)Aprimitiveissuedbyaserviceprovidertoacknowledgeorcompletesomeprocedurepreviouslyinvokedbyarequestbytheserviceuser43ServicePrimitives（原語(yǔ)）andParametersdefineservicesbetweenadjacentlayersusing:primitivestospecifyfunctionperformedparameterstopassdataandcontrolinfo44Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體45InternetApplicationsApplicationsthatoperateontopofTCPinclude:SMTPFTPSSHTCP46Contents為什么需要協(xié)議體系結(jié)構(gòu)簡(jiǎn)化的協(xié)議體系結(jié)構(gòu)TCP/IP協(xié)議體系結(jié)構(gòu)標(biāo)準(zhǔn)化的協(xié)議體系結(jié)構(gòu)傳統(tǒng)的互聯(lián)網(wǎng)應(yīng)用多媒體47MultimediaTerminology48MultimediaTerminologyaudiogenerallyencompassessoundsthatareproducedbyahuman,telephonyandrelatedvoicecommunicationstechnologyimagesupportsthecommunicationofindividualpictures,charts,ordrawingsvideoservicecarriessequencesofpicturesintimetextisinformationthatcanbeenteredviaakeyboardandisdirectlyreadableandprintable49MultimediaApplicationsMultimediainformationsystems

databases,informationkiosks,hypertexts,electronicbooks,andmultimediaexpertsystemsMultimediacommunicationsystems

computer-supportedcollaborativework,videoconferencing,streamingmedia,andmultimediateleservicesMultimediaentertainmentsystems

3Dcomputergames,multiplayernetworkgames,infotainment,andinteractiveaudiovisualproductionsMultimediabusinesssystems

immersiveelectroniccommerce,marketing,multimediapresentations,videobrochures,virtualshoppingMultimediaeducationalsystems

electronicbooks,flexibleteachingmaterials,simulationsystems,automatictesting,distancelearning50DomainsofMultimediaSystemsandExampleApplications51ElasticandInelasticTrafficcanadjusttodelayandthroughputchangesacrossaninternet-traditional“data”styleTCP/IPtrafficdoesnoteasilyadapttochangesindelayandthroughput-“real-time”trafficsuchasvoiceandvideoElasticTraffic彈性流量InelasticTraffic非彈性流量52MultimediaTechnologies53SummaryintroducedneedforprotocolarchitectureTCP/IPprotocolarchitectureprotocolarchitecturestandardizationmultimediaapplicationneeds協(xié)議的關(guān)鍵要素TCP/IP協(xié)議體系結(jié)構(gòu)54AssignmentsPart12.1Multiplechoice1.WhichofthefollowingisNOTthekeyelementsofaprotocol?A.syntax

B.semantics

C.rule

D.timing

552.1Multiplechoice2-5.ThelayersinTCP／IPprotocolarchitectureare2

,Intransportlayer,TCPprovides3

datatransmission，andUDPprovides4datatransmission.Innetworklayer,IPprovides

5packettransmission.

2.A．transportlayer,internetlayer,networkaccesslayer,physicallayerB．a(chǎn)pplicationlayer,transportlayer,internetlayer,networkaccesslayer,physicallayerC．transportlayer,internetlayer,ATMlayer,physicallayerD．transportlayer,networklayer,datalinklayer,physicallayer3.A．connectionoriented,notreliableB．connectionless,notreliableC．connectionoriented,reliableD．connectionless,reliable4.A．connectionlessB．connectionorientedC．connectionless,reliableD．connectionoriented,notreliable5.A．connectionoriented,reliableB．connectionless,reliableC．connectionoriented,notreliableD．connectionless,notreliable562.1Multiplechoice6.Networkarchitecturecanbedefinedas：A.animplementationofcomputernetworksB.asoftwaremoduletoimplementtechniquesanddataprocessingC.asetofrulesandstandardstosetuporusehardware(software)forcommunication.D.astandarddefinedbyISO.7.Communicationsystemhasdifferentkindsofconnections.Internetconnectionis

ina:A.pointtopointlinkB.MultinodebroadcastnetworkC.switchingnetworkD.Packetswitchingnetwork

572.1Multiplechoice8.ThelayersofTCP/IPprotocolarchitectureare(fromtoptobottom):A.application,session,transport,networkaccess,physicalB.application,transport,network,datalink,physicalC.application,transport,internet,networkaccess,physicalD.application,presentation,transport,internet,networkaccess

582.1Multiplechoice9.Regardlessofthenatureoftheapplicationsthatareexchangingdata,thereisusuallyarequirementthatdatabeexchangedreliably，thisisreferredtoasthe（）.A.transportlayerB.applicationlayerC.physicallayerD.networkaccesslayer592.1Multiplechoice10.Thecombinationofdatafromthenexthigherlayerandcontrolinformationisknownasa().

A.datalink B.headerC.protocoldataunit D.sequencenumber

11.The()layerisconcernedwiththeexchangeofdatabetweenanendsystem(server,workstation,etc.)andthenetworktowhichitisattached.

A.transport B.applicationC.networkaccess D.physical602.1Multiplechoice12.Themainfunctionofthephysicallayeristotransfer（）correctly.A.bitstreamB.framesC.packetsD.datagram13.The()isusedatthislayertoprovidetheroutingfunctionacrossmultiplenetworks.A.TransmissionControlProtocol

B.InternetProtocolC.UserDatagramProtocolD.FileTransferProtocol612.2TermsDefinitionProtocolPDUFileTransferProtocolInternetProtocolUserDatagramProtocol622.3FillintheBlanksInlayeredmodel,whenapplicationdatatransmitfromupperlayertolowerlayer,eachlayerappendsa____,containingprotocolcontrolinformation.Thepeerlayerscommunicatebymeansofformattedblocksofdatathatobeyasetofrulesorconventionsknownasa____.

632.4AnswerQuestions

1.Whatarethekeyfeaturesofaprotocol?2.GivethefunctionsofeachlayerofTCP/IP.64AssignmentsPart22.5MultipleChoice1.Thepurposeofflowcontrolis:A.errorcontrolling B.timingC.orderdelivery D.topreventreceiveroverload2.Eachprocesswithahostmusthaveanaddressthatisuniquewithinthehost;thisallowsthehost-to-hostprotocol(TCP)todeliverdatatotheproperprocess.Theseaddressesareknownas()：A.globalinternetaddressB.portsC.networkaddressD.computeraddress652.5MultipleChoice3.The()isconcernedwithspecifyingthecharacteristicsofthetransmissionmedium,thenatureofthesignals,thedatarate,andrelatedmatters.A.NetworkaccesslayerB.physicallayerC.transportlayerD.Internetlayer4.IPappendsaheaderofcontrolinformationtoeachsegmenttoforman().A.IPsegmentB.IPpacketC.IPstream

D.IPdatagram662.5MultipleChoice5.Communicationbetweenpeerlayeratdifferentnodesneeds：A.interfaceB.peerprotocolC.electricalsignalD.transmissionmedia6.()characteristicofthephysicallayerrelatestothephysicalpropertiesoftheinterfacetoatrans