chap04-Protocols-and-the-TCPIP-Suite-无线网络通信-英文课件

ProtocolsandtheTCP/IPSuiteChapter4ProtocolsandtheTCP/IPSuite1KeyFeaturesofaProtocolSyntaxConcernstheformatofthedatablocksSemanticsIncludescontrolinformationforcoordinationanderrorhandlingTimingIncludesspeedmatchingandsequencingKeyFeaturesofaProtocolSyntAgentsInvolvedinCommunicationApplicationsExchangedatabetweencomputers(e.g.,electronicmail)ComputersConnectedtonetworksNetworksTransfersdatafromonecomputertoanotherAgentsInvolvedinCommunicatichap04-Protocols-and-the-TCPIP-Suite-无线网络通信-英文课件chap04-Protocols-and-the-TCPIP-Suite-无线网络通信-英文课件TCP/IPNetworkAccessLayerConcernedwiththeexchangeofdatabetweenanendsystemandthenetworktowhichit'sattachedSoftwareuseddependsontypeofnetworkCircuitswitchingPacketswitching(e.g.,X.25)LANs(e.g.,Ethernet)OthersTCP/IPNetworkAccessLayerConT:TCP/IPInternetLayerUsesinternetprotocol(IP)ProvidesroutingfunctionstoallowdatatotraversemultipleinterconnectednetworksImplementedinendsystemsandroutersT:TCP/IPInternetLayerUsesinTCP/IPHost-to-Host,orTransportLayerCommonlyusestransmissioncontrolprotocol(tcp)ProvidesreliabilityduringdataexchangeCompletenessOrderTCP/IPHost-to-Host,orTranspTCP/IPApplicationLayerLogicsupportsuserapplicationsUsesseparatemodulesthatarepeculiartoeachdifferenttypeofapplicationTCP/IPApplicationLayerLogicProtocolDataUnits(PDUs)ProtocolDataUnits(PDUs)CommonTCP/IPApplicationsSimplemailtransferprotocol(SMTP)ProvidesabasicelectronicmailfacilityFileTransferProtocol(FTP)AllowsfilestobesentfromonesystemtoanotherTELNETProvidesaremotelogoncapabilityCommonTCP/IPApplicationsSimpLayersoftheOSIModelApplicationPresentationSessionTransportNetworkDatalinkPhysicalLayersoftheOSIModelApplicaOSIApplicationLayerProvidesaccesstotheOSIenvironmentforusersProvidesdistributedinformationservicesOSIApplicationLayerProvidesOSIPresentationLayerProvidesindependencetotheapplicationprocessesfromdifferencesindatarepresentation(syntax)OSIPresentationLayerProvidesOSISessionLayerProvidesthecontrolstructureforcommunicationbetweenapplicationsEstablishes,manages,andterminatesconnections(sessions)betweencooperatingapplicationsOSISessionLayerProvidestheOSITransportLayerProvidesreliable,transparenttransferofdatabetweenendpointsProvidesend-to-enderrorrecoveryandflowcontrolOSITransportLayerProvidesreOSINetworkLayerProvidesupperlayerswithindependencefromthedatatransmissionandswitchingtechnologiesusedtoconnectsystemsResponsibleforestablishing,maintaining,andterminatingconnectionsOSINetworkLayerProvidesuppeOSIDatalinkLayerProvidesforthereliabletransferofinformationacrossthephysicallinkSendsblocks(frames)withthenecessarysynchronization,errorcontrol,andflowcontrolOSIDatalinkLayerProvidesfoOSIPhysicalLayerConcernedwithtransmissionofunstructuredbitstreamoverphysicalmediumDealswithaccessingthephysicalmediumMechanicalcharacteristicsElectricalcharacteristicsFunctionalcharacteristicsProceduralcharacteristicsOSIPhysicalLayerConcernedwiComparisonofOSIandTCP/IPComparisonofOSIandTCP/IPTCP/IPArchitectureDominanceTCP/IPprotocolsmaturedquickerthansimilarOSIprotocolsWhentheneedforinteroperabilityacrossnetworkswasrecognized,onlyTCP/IPwasavailableandreadytogoOSImodelisunnecessarilycomplexAccomplishesinsevenlayerswhatTCP/IPdoeswithfewerlayersTCP/IPArchitectureDominanceTElementsofStandardizationwithinOSIFrameworkProtocolSpecificationFormatofprotocoldataunits(PDUs)exchangedSemanticsofallfieldsAllowablesequenceofPDUsServiceDefinitionFunctionaldescriptionthatdefineswhatservicesareprovided,butnothowtheservicesaretobeprovidedAddressingEntitiesarereferencedbymeansofaserviceaccesspoint(SAP)ElementsofStandardizationwiInternetworkingTermsCommunicationnetwork–facilitythatprovidesadatatransferserviceamongdevicesattachedtothenetworkInternet–collectionofcommunicationnetworks,interconnectedbybridges/routersIntranet–internetusedbyanorganizationforinternalpurposesProvideskeyInternetapplicationsCanexistasanisolated,self-containedinternetInternetworkingTermsCommunicaInternetworkingTermsEndSystem(ES)–deviceusedtosupportend-userapplicationsorservicesIntermediateSystem(IS)–deviceusedtoconnecttwonetworksBridge–anISusedtoconnecttwoLANsthatusesimilarLANprotocolsRouter-anISusedtoconnecttwonetworksthatmayormaynotbesimilarInternetworkingTermsEndSysteFunctionsofaRouterProvidealinkbetweennetworksProvidefortheroutinganddeliveryofdatabetweenprocessesonendsystemsattachedtodifferentnetworksProvidethesefunctionsinsuchawayasnottorequiremodificationsofthenetworkingarchitectureofanyoftheattachedsubnetworksFunctionsofaRouterProvideaNetworkDifferencesRoutersMustAccommodat