C語言雙語課件 CHAPTER2

計算機(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語法語義時序關(guān)系6Contents為什么需要協(xié)議體系結(jié)構(gòu)簡化的協(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？優(yōu)缺點？三層簡單協(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)中的兩級地址是？靠什么來傳遞對等層協(xié)議相關(guān)信息？協(xié)議體系結(jié)構(gòu)的工作？TCP/IP協(xié)議包括哪五個部分？36Contents為什么需要協(xié)議體系結(jié)構(gòu)簡化的協(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)議分層的理解請舉一日常生活中的例子來形象地描述該模型中各層的peer-to-peerprotocol（對等協(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)寫信的例子

張明寫信李強(qiáng)讀信

封入信封拆開信封投入信箱從信箱中取信件收信分檢裝郵包開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層對等協(xié)議第1層對等協(xié)議第3層對等協(xié)議第4層對等協(xié)議寫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請求AprimitiveissuedbyaserviceusertoinvokesomeserviceandtopasstheparametersneededtospecifyfullytherequestedserviceINDICATION指示Aprimitiveissuedbyaserviceprovidereitherto:indicatethataprocedurehasbeeninvokedbythepeerserviceuserontheconnectionandtoprovidetheassociatedparameters,ornotifytheserviceuserofaprovider-initiatedactionRESPONSE

響應(yīng)AprimitiveissuedbyaserviceusertoacknowledgeorcompletesomeprocedurepreviouslyinvokedbyanindicationtothatuserCONFIRM

證實Aprimitiveissuedbyaserviceprovidertoacknowledgeorcompletesomeprocedurepreviouslyinvokedbyarequestbytheserviceuser43ServicePrimitives（原語）andParametersdefineservicesbetweenadjacentlayersusing:primitivestospecifyfunctionperformedparameterstopassdataandcontrolinfo44Contents為什么需要協(xié)議體系結(jié)構(gòu)簡化的協(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