互联网协议(PPT45)(1)

InternetProtocolOverview1.0TCP/IPandtheDoDModel2.0IPAddressing3.0Subnetting1.0TCP/IPandtheDoDModel1.1ComparisonofDodandOSIModel1.2TheTCP/IPprotocolsuite1.3TheProcess/ApplicationlayerProtocols1.4TheHost-to-HostLayerProtocols1.5TheInternetLayerProtocols1.1ComparisonofDoDandOSIModel(1)TheTCP/IPsuitewascreatedbytheDoDTheDoDmodelisacondensedversionoftheOSImodelApplicationPresentationSessionTransportNetworkDataLinkPhysicalProcess/ApplicationHost-to-HostInternetNetworkAccessDoDModelOSIModel•Node-to-nodeapplicationcommunication•Controlsuser-interfacespecifications•Settinguptheleveloftransmissionserviceforapplications•TakescareIPaddressanddesignateprotocolsforlogicaltransmissionofpacketsovertheentirenetwork•Overseeshardwareaddressinganddefinesprotocolsforthephysicaltransmissionofdata1.1ComparisonofDoDandOSIModel(2)TCP/IPModelOSIModel1.2TheTCP/IPProtocolSuiteProcess/ApplicationTelnetTCPUDPIPICMPARPLANTechnologies:Ethernet,FastEthernet,TokenRing,FDDIWANTechnologies:SerialLines,FrameRelay,ATMRARPHost-to-HostInternetNetworkAccessFTPTFTPSMTPLPDSNMPNFSXWindowBootP/DHCPDNSIGMP1.3TheProcess/ApplicationLayerProtocolsTelnet–TelephoneNetworkFTP–FileTransferProtocolTFTP–TrivialFileTransferProtocolNFS–NetworkFileSystemSMTP–SimpleMailTransferProtocolLPD–LinePrinterDaemonXWindow–writingaGUI-basedclient/serverapplicationsDNS–DomainNameService(DNS)BootP–BootstrapProtocolDHCP–DynamicHostConfigurationProtocol1.4TheHost-to-HostLayerProtocolsToshieldtheupper-layerapplicationsfromthecomplexitiesofthenetworkTCP(TransmissionControlProtocol)BreakdowndatafromupperlayersintoSegmentNumbersandsequenceseachsegmentConnection-oriented–virtualcircuitrequiredUserDatagramProtocol(UDP)BreakdowndatabutnotsequencethesegmentThinprotocolwhichdoesn’ttakeupmuchbandwidthonanetworkConnectionless–novirtualcircuitrequired,thusunreliableForsendinglittlemessageandreliabilityaccomplishedattheupperlayers1.4aTransmissionControlProtocol(TCP)Connection-orientedSessionisestablishedbeforeexchangingdataVirtualcircuitrequiredReliableDeliverySequencenumbersAcknowledgments(ACKs)Doesn’ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate1.4bTCPThree-WayHandshakeApplicationTransportInternetNetworkDataApplicationTransportInternetNetworkData,ACK(+startbyte)ACK1.4cTCPSegmentFormat1.4dUserDatagramProtocol(UDP)ConnectionlessNosessionisestablishedDoesNotGuaranteeDeliveryNosequencenumbersNoacknowledgmentsLowoverheadReliabilityIstheResponsibilityoftheApplicationDoesn’ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate1.4eUDPSegmentFormatLowoverheadNosequencenumberNoAcknowledgementnumberNowindowssizeTransportApplicationInternetNetwork1.4fPortsNumbers(1)TCPandUDPmustuseportnumberstocommunicatewiththeupperlayers.Portnumberskeeptrackofdifferentconversationscrossingthenetworksimultaneously.TFTPServerWebServer0...655350...65535TCPPorts20,21UDPPort69TCPPort80WindowsSocketsInterfaceTCPProtocolNo.6UDPProtocolNo.17IPFTPServerSMTPTCPPort25DNSUDPPort53POP3UDPPort110SNMPUDPPort1611.4gPortNumbers(2)No.below1024Well-knownportno.definedinRFC1700UsuallyindestinationporttotellthereceivinghostthepurposeoftheintendedconnectionNo.1024andaboveusedbyupperlayers(randomlychosen)tosetupsessionswithotherhostsUsedbyTCPtouseassourceanddestinationaddressesintheTCPsegmentUsuallyinSourceporttodifferentiatebetweensessionswithdifferentsourcehosts1.5TheInternetLayerProtocolsForroutingandprovidingasinglenetworkinterfacetotheupperlayerlayers.AllnetworkpathsthroughthemodelgothroughIP.ProtocolsworksattheInternetLayer:InternetProtocol(IP)–essentiallyistheInternetLayer,andotherprotocolsfoundheremerelyexisttosupportit.InternetControlMessageProtocol(ICMP)AddressResolutionProtocol(ARP)ReverseAddressResolutionProtocol(RARP)1.5aInternetProtocol(IP)AddressesandRoutesPacketsaccordingtotheRoutingTableFragmentsandReassemblesDatagrams/PacketsConnectionlessNosessionisestablishedNonguaranteed“BestEffort”DeliveryReliabilityIstheResponsibilityofHigher-LayerProtocolsandApplications1.5bIPheader*Protocolnumber:01–ICMP,06–TCP,17–UDP,etc.1.5cInternetControlMessageProtocol(ICMP)ManagementProtocolandmessagingserviceproviderforIP.Inroutersolicitation,ICMPisusedtosendthefollowingeventsandmessages(intheDataarea):DestinationUnreachableBufferFullHopsPingTraceroute1.5dAddressResolutionProtocol(ARP)SuccessfulMappingofanIPAddresstoaHardwareAddressARPUsesaLocalBroadcasttoObtainaHardwareAddressAddressMappingsAreStoredinaCacheforFutureReference1.5eResolvingalocalIPAddressARPCache150.107.7.2808004...ARPCache150.107.7.2808004...4IPAddress=150.107.7.28HardwareAddress=08004...IPAddress=150.107.7.29HardwareAddress=08007...3HardwareAddress=08007...21ping150.107.7.29ARPBroadcast1.5fResolvingaRemoteIPAddressARouterBIPAddress=150.107.3.24HardwareAddress=08004...IPAddress=150.107.7.29HardwareAddress=08009...ARPCache150.107.7.708009...150.107.7.108006...ARPCache150.107.3.708004...41150.107.3.108005...150.107.7.108006...25ping150.107.7.29ARPCache3N