2023学年完整公开课版OSPF

《HCNA-HNTDFastTraining》LinkStateRoutingwithOSPF课程团队：叶礼兵王苏南张悦吴伟强Foreword OSPFisaninteriorgatewayprotocol(IGP)designedforIPnetworks,thatisfoundedontheprinciplesoflinkstaterouting.Thelinkstatebehaviorprovidesmanyalternativeadvantagesformediumandevenlargeenterprisenetworks.ItsapplicationasanIGPisintroducedalongwithinformationrelevanttotheunderstandingofOSPFconvergenceandimplementation,forsupportingOSPFinenterprisenetworks.Page2Objectives Uponcompletionofthissection,traineeswillbeableto:ExplaintheOSPFconvergenceprocessDescribethedifferentnetworktypessupportedbyOSPFSuccessfullyconfiguresingleareaOSPFnetworksPage3OpenShortestPathFirst（OSPF）Page4SiteBSiteASiteCOSPFRTARTBRTCRIPOSPFOSPFoverMPLSMinimalRoutingTrafficRapidConvergenceScalableAccurateRouteMetricsOSPFConvergenceBehaviorPage5destinationnexthopcost...............LSAFloodingLSDBLSAofRTALSAofRTBLSAofRTCSPF

AlgorithmRouteCalculationShortestPathTreeIP

RoutingTableSiteAOSPFRTARTBRTCRouterIDPage63.3.3.31.1.1.12.2.2.2RTARTBRTCArouterIDisa32bitvalueusedtoidentifyeachrouterrunningtheOSPFprotocol.OSPFSupportedNetworkTypesPage7Broadcast1.1.1.12.2.2.2RTARTB4.4.4.43.3.3.3RTDRTCEthernetbasednetworksadoptthebroadcastnetworktypebydefault.OSPFSupportedNetworkTypesPage8Point-to-Point1.1.1.12.2.2.2RTARTB2.2.2.2RTB1.1.1.1RTABroadcastSerialtechnologiessuchasPPPandHDLCwilldefaulttothePoint-to-Pointnetworktype.OSPFSupportedNetworkTypesPage9PointtoMulti-PointATM/FRVirtualCircuitVirtualCircuitNon-BroadcastMulti-Access(NBMA)ATM/FRDRVirtualCircuitVirtualCircuitATM&FrameRelaydefaulttoNon-BroadcastMulti-Access.DesignatedRouter&BackupDesignatedRouterPage10BDRDRRTARTBRTCRTD1.1.1.12.2.2.23.3.3.34.4.4.4DesignatedRouterslimitthenumberofadjacenciesnecessaryinbroadcast(Ethernet)networks.NeighborStatesPage11NeighborAdjacentAdjacentBDRDRRTARTBRTCRTD1.1.1.12.2.2.23.3.3.34.4.4.4Definesformofrelationshipbetweenneighbors.Twoneighborstatesarepossible,neighborandadjacent.LinkStateEstablishmentPage12DownInitExStartLoadingFullNeighborAdjacent2-WayExchangeAttemptStatechangesallowforneighborrelationshipstobeachieved.NeighborDiscoveryPage13TheHelloprotocolisresponsibleforneighbordiscoveryandmaintenancefortwowaycommunicationbetweenneighbors.HelloHelloRTARTBRouterPriorityDesignatedRouterBackupDesignatedRouterHelloIntervalRouterDeadIntervalOptionsNeighborDesignatedRouterElectionPage14ADesignatedRouteriselectedbasedonthepriorityvalue.[RTD]interfaceGigabitEthernet0/0/0[RTD-GigabitEthernet0/0/0]ospfnetwork-typep2pDR(Priority=255)BroadcastPriority=0DR(Priority=255)BroadcastRTARTBRTCRTD(Priority=1)BackupDesignatedRouterElectionPage15TheBackupDesignatedRouter(BDR)formsadjacencieswithallotherroutersandwillbecometheDRiftheexistingDRfails.RTCPriority=0DR(Priority=255)BroadcastRTARTBPoint-to-PointBDRRTD(Priority=1)DatabaseSynchronizationPage16RTA(RouterID:1.1.1.1)RTB(RouterID:2.2.2.2)DD,(Master)(Sequence=X)DD,(Master)(Sequence=Y)DD,(Slave)(Sequence=Y)DD,(Master)(Sequence=Y+1)DD,(Master)(Sequence=Y+1)Neighboringroutersformamaster/slaverelationship.DatabaseDescriptionpacketscontainLSAheaderinformation.EstablishingFullAdjacencyPage17LinkStateUpdateLinkStateRequestLinkStateUpdateLinkStateRequestLoadingFullRTA(RouterID:1.1.1.1)RTB(RouterID:2.2.2.2)MissingornewerinstancesofLSAarerequestedusingLSRTheentirerequestedLSAissentasanupdate.OSPFMetricPage18Thecostmetricisbasedontheformula108/bandwidthThebandwidthreferencecommandimprovesmetricaccuracy[RTA]interfaceGigabitEthernet0/0/0[RTA-GigabitEthernet0/0/0]ospfcost20RTA(RouterID:1.1.1.1)RTB(RouterID:2.2.2.2)[RTB]ospf[RTB-ospf-1]bandwidth-reference10000G0/0/0ShortestPathTreePage1910.0.0.0/8RTARTBRTCRTDRTE[RTC]displayiprouting-table……Destination/MaskProtoPreCostFlagsNextHopInterface

10.0.0.0/8OSPF1020D192.168.1.4G0/0/020.0.0.0/8OSPF1020D192.168.1.4G0/0/0

OSPF1020D192.168.2.1G0/0/120.0.0.0/8192.168.1.0/24192.168.2.0/24EachroutercalculatestheshortestpathtoallothernetworksOSPFAreas–SingleAreaPage20RTARTBRTCRTFRTDRTEArea0Asinglelinkstatedatabasefortheadministrativedomain.Anyareanumbercanbeassignedbutarea0isrecommended.OSPFAreas–MultiAreaPage21AreasbuildseparateLSdatabases,minimizeimpactofchangeArea1Area2Area3RTARTBRTCRTFRTDRTEArea0OSPFNetworkAdvertisementPage22ThenetworkcommanddefinesthenetworktobeadvertisedRouteadvertisementsareforwardedbasedonareas.RTARTB.2192.168.1.0/24.1G0/0/0G0/0/0[RTA]ospf1router-id1.1.1.1[RTA-ospf-1]area0[RTA-ospf-1-area-0.0.0.0]network192.168.1.00.0.0.255RouterID:1.1.1.1RouterID:2.2.2.2Area0ConfigurationValidationPage23[RTA]displayospfpeerOSPFProcess1withRouterID1.1.1.1NeighborsArea0.0.0.0interface192.168.1.1(GigabitEthernet0/0/0)'sneighborsRouterID:2.2.2.2Address:192.168.1.2State:FullMode:NbrisMasterPriority:1DR:192.168.1.2BDR:192.168.1.1MTU:0Deadtimerduein40secRetranstimerinterval:5Neighborisupfor00:00:31AuthenticationSequence:[0]OSPFAuthenticationPage24RTARTBPassword:huawei[RTA]interfaceGigabitEthernet0/0/0[RTA-GigabitEthernet0/0/0]ospfauthentication-modemd51huaweiG0/0/0G0/0/0OSPFsupportstwoformsofauthentication,simplepasswordorcryptographicauthentication.ConfigurationValidationPage25<RTA>terminaldebugging<RTA>debuggingospfpacketAug19201308:10:06.850.2+00:00RTARM/6/RMDEBUG:SourceAddress:192.168.1.1Aug19201308:10:06.850.3+00:00RTARM/6/RMDEBUG:DestinationAddress:224.0.0.5……Aug19201308:10:06.850.6+00:00RTARM/6/RMDEBUG:Area:0.0.0.0,Chksum:0Aug19201308:10:06.850.7+00:00RTARM/6/RMDEBUG:AuType:02Aug19201308:10:06.850.8+00:00RTARM/6/RMDEBUG:Key(ascii):********OSPFSilentInterfacePage26[RTA]ospf[RTA-ospf-1]silent-interfaceGigabitEthernet0/0/0RTARTB192.168.1.0/24G0/0/0G0/0/0Thesilent-interfacecommandpreventsaninterfacefromformingneighborrelationshipswithpeer