tanenbaum《计算机网络》原版第1章课件

IntroductionChapter1UsesofComputerNetworks•BusinessApplications•HomeApplications•MobileUsers•SocialIssuesBusinessApplicationsofNetworksAnetworkwithtwoclientsandoneserver.BusinessApplicationsofNetworks(2)Theclient-servermodelinvolvesrequestsandreplies.HomeNetworkApplications•Accesstoremoteinformation•Person-to-personcommunication•Interactiveentertainment•ElectroniccommerceHomeNetworkApplications(2)Inpeer-to-peersystemtherearenofixedclientsandservers.HomeNetworkApplications(3)Someformsofe-commerce.MobileNetworkUsersCombinationsofwirelessnetworksandmobilecomputing.NetworkHardware•LocalAreaNetworks•MetropolitanAreaNetworks•WideAreaNetworks•WirelessNetworks•HomeNetworks•InternetworksBroadcastNetworksTypesoftransmissiontechnology•Broadcastlinks•Point-to-pointlinksBroadcastNetworks(2)Classificationofinterconnectedprocessorsbyscale.LocalAreaNetworksTwobroadcastnetworks(a)Bus(b)RingMetropolitanAreaNetworksAmetropolitanareanetworkbasedoncableTV.WideAreaNetworksRelationbetweenhostsonLANsandthesubnet.WideAreaNetworks(2)Astreamofpacketsfromsendertoreceiver.WirelessNetworksCategoriesofwirelessnetworks:•Systeminterconnection•WirelessLANs•WirelessWANsWirelessNetworks(2)(a)Bluetoothconfiguration(b)WirelessLANWirelessNetworks(3)(a)Individualmobilecomputers(b)AflyingLANHomeNetworkCategories•Computers(desktopPC,PDA,sharedperipherals•Entertainment(TV,DVD,VCR,camera,stereo,MP3)•Telecomm(telephone,cellphone,intercom,fax)•Appliances(microwave,fridge,clock,furnace,airco)•Telemetry(utilitymeter,burglaralarm,babycam).NetworkSoftware•ProtocolHierarchies•DesignIssuesfortheLayers•Connection-OrientedandConnectionlessServices•ServicePrimitives•TheRelationshipofServicestoProtocolsNetworkSoftwareProtocolHierarchiesLayers,protocols,andinterfaces.ProtocolHierarchies(2)Thephilosopher-translator-secretaryarchitecture.ProtocolHierarchies(3)Exampleinformationflowsupportingvirtualcommunicationinlayer5.DesignIssuesfortheLayers•Addressing•ErrorControl•FlowControl•Multiplexing•RoutingConnection-OrientedandConnectionlessServicesSixdifferenttypesofservice.ServicePrimitivesFiveserviceprimitivesforimplementingasimpleconnection-orientedservice.ServicePrimitives(2)Packetssentinasimpleclient-serverinteractiononaconnection-orientednetwork.ServicestoProtocolsRelationshipTherelationshipbetweenaserviceandaprotocol.ReferenceModels•TheOSIReferenceModel•TheTCP/IPReferenceModel•AComparisonofOSIandTCP/IP•ACritiqueoftheOSIModelandProtocols•ACritiqueoftheTCP/IPReferenceModelReferenceModelsTheOSIreferencemodel.ReferenceModels(2)TheTCP/IPreferencemodel.ReferenceModels(3)ProtocolsandnetworksintheTCP/IPmodelinitially.ComparingOSIandTCP/IPModelsConceptscentraltotheOSImodel•Services•Interfaces•ProtocolsACritiqueoftheOSIModelandProtocolsWhyOSIdidnottakeovertheworld•Badtiming•Badtechnology•Badimplementations•BadpoliticsBadTimingTheapocalypseofthetwoelephants.ACritiqueoftheTCP/IPReferenceModelProblems:•Service,interface,andprotocolnotdistinguished•Notageneralmodel•Host-to-network“layer”notreallyalayer•Nomentionofphysicalanddatalinklayers•Minorprotocolsdeeplyentrenched,hardtoreplaceHybridModelThehybridreferencemodeltobeusedinthisbook.ExampleNetworks•TheInternet•Connection-OrientedNetworks:X.25,FrameRelay,andATM•Ethernet•WirelessLANs:802:11TheARPANET(a)Structureofthetelephonesystem.(b)Baran’sproposeddistributedswitchingsystem.TheARPANET(2)TheoriginalARPANETdesign.TheARPANET(3)GrowthoftheARPANET(a)December1969.(b)July1970.(c)March1971.(d)April1972.(e)September1972.NSFNETTheNSFNETbackbonein1988.InternetUsageTraditionalapplications(1970–1990)•E-mail•News•Remotelogin•FiletransferArchitectureoftheInternetOverviewoftheInternet.ATMVirtualCircuitsAvirtualcircuit.ATMVirtualCircuits(2)AnATMcell.TheATMReferenceModelTheATMreferencemodel.TheATMReferenceModel(2)TheATMlayersandsublayersandtheirfunctions.EthernetArchitectureoftheoriginalEthernet.WirelessLANs(a)Wirelessnetworkingwithabasestation.(b)Adhocnetworking.WirelessLANs(2)Therangeofasingleradiomaynotcovertheentiresystem.WirelessLANs(3)Amulticell802.11network.NetworkStandardization•Who’sWhointheTelecommunicationsWorld•Who’sWhointheInternationalStandardsWorld•Who’sWhointheInternetStandardsWorldITU•Mainsectors•Radiocommunications•TelecommunicationsStandardization•Development•ClassesofMembers•Nationalgovernments•Sectormembers•Associatemembers•RegulatoryagenciesIEEE802StandardsThe802workinggroups.Theimportantonesaremarkedwith*.Theonesmarkedwitharehibernating.Theonemarkedwith†gaveup.MetricUnitsTheprincipalmetricprefixes.