IP header - Study CCNA

Version – the version of the IP protocol. · Header length – the length of the header in 32-bit words. · Priority and Type of Service – specifies how the datagram ... SkiptocontentMenuAnIPheaderisaprefixtoanIPpacketthatcontainsinformationabouttheIPversion,lengthofthepacket,sourceanddestinationIPaddresses,etc.Itconsistsofthefollowingfields:Hereisadescriptionofeachfield:Version–theversionoftheIPprotocol.ForIPv4,thisfieldhasavalueof4.Headerlength–thelengthoftheheaderin32-bitwords.Theminumumvalueis20bytes,andthemaximumvalueis60bytes.PriorityandTypeofService–specifieshowthedatagramshouldbehandled.Thefirst3bitsaretheprioritybits.Totallength–thelengthoftheentirepacket(header+data).Theminimumlengthis20bytes,andthemaximumis65,535bytes.Identification–usedtodifferentiatefragmentedpacketsfromdifferentdatagrams.Flags–usedtocontroloridentifyfragments.Fragmentedoffset–usedforfragmentationandreassemblyifthepacketistoolargetoputinaframe.Timetolive–limitsadatagram’slifetime.Ifthepacketdoesn’tgettoitsdestinationbeforetheTTLexpires,itisdiscarded.Protocol–definestheprotocolusedinthedataportionoftheIPdatagram.Forexample,TCPisrepresentedbythenumber6andUDPby17.Headerchecksum–usedforerror-checkingoftheheader.Ifapacketarrivesatarouterandtheroutercalculatesadifferentchecksumthantheonespecifiedinthisfield,thepacketwillbediscarded.SourceIPaddress–theIPaddressofthehostthatsentthepacket.DestinationIPaddress–theIPaddressofthehostthatshouldreceivethepacket.Options–usedfornetworktesting,debugging,security,andmore.Thisfieldisusuallyempty. ConsiderthefollowingIPheader,capturedwithWireshark:Noticethefieldsintheheader:theIPversionisIPv4,theheaderlengthis20bytes,theupper-levelprotocolusedisTCP,theTTLvalueissettu128,sourceanddestinationIPaddressesarelisted,etc.DownloadourFreeCCNAStudyGuidePDFforcompletenotesonalltheCCNA200-301examtopicsinonebook.WerecommendtheCiscoCCNAGoldBootcampasyourmainCCNAtrainingcourse.It’sthehighestratedCiscocourseonlinewithanaverageratingof4.8fromover30,000publicreviewsandisthegoldstandardinCCNAtraining:PostnavigationUDPexplainedUnicast,multicast,andbroadcastaddressesCCNA200-301TutorialsIntroductionAboutUsWhatisCCNA?NewCCNAexam-200-301FreeCiscoCCNAStudyGuideRecommendedCCNAStudyResourcesIntroductiontoNetworkingWhatisaNetwork?LocalAreaNetwork(LAN)OSI&TCP/IPModelsTCP/IPSuiteofProtocolsEncapsulationCiscoOperatingSystemIOSCiscoIOSOverviewPortsonanIOSDeviceAuxiliaryPortonaCiscoRouterCiscoConsoleRolloverCableGetHelpinIOSIOSCommandModesRunPrivilegedCommandsWithinGlobalConfigModePipeCharacterinIOSRunning&StartupConfigurationTheTransportLayerTransportLayerExplanation–Layer4oftheOSIModelPortsExplainedTCPExplainedTCPThree-WayHandshakeUDPexplainedTheNetworkLayerIPHeaderUnicast,Multicast,andBroadcastAddressesTypesofIPAddressesIPv4AddressingWhatisIpv4AddressandWhatisitsRoleintheNetwork?ConvertingtheIPAddress-DecimaltoBinarySubnetMaskClassesofIPAddressesSubnettingSubnettingExplainedCIDR(ClasslessInter-DomainRouting)CreateSubnetsUnderstandingVariableLengthSubnetMasks(VLSM)PrivateIPAddressesExplainedTheData-LinkLayerEthernetExplainedEthernetFrameMAC&IPAddressesThePhysicalLayerTypesofEthernetCablingIEEEEthernetStandardsTypesofEthernetCables–Straight-ThroughandCrossoverCiscoPoEExplained-WhatisPoweroverEthernet?CiscoNetworkDevicesNetworkDevicesNetworkHubsExplainedNetworkSwitchExplainedCSMA/CDCollision&BroadcastDomainHowSwitchesWorkLayer2SwitchingNetworkRouterExplainedWhatIsLayer3SwitchandHowitWorksinOurNetwork?LifeofaPacketWhatisDomainNameSystem(DNS)andHowDoesitWork?MapHostnamestoIPAddressesConfigureCiscoDeviceasDNSclientHowtoConfigureaCiscoRouterasaDNSServer?noipdomain-lookupCommandARP(AddressResolutionProtocol)ExplainedTheARPTableonaCiscoRouterRouter&SwitchBasicConfigurationIOSBasicCommandsConfigureanIPAddressonaSwitchConfigureDescriptionsInterfaceRangeCommandPoweronaCiscoDeviceHalfDuplexandFullDuplexConfigureSpeedandDuplexLinkLayerDiscoveryProtocol(LLDP)CiscoDiscoveryProtocol(CDP)overviewshowCommandshowinterfacesstatusCommandInterfaceStatusCodesshowversionCommandCiscoDeviceManagementTypesofMemoryonaCiscoDeviceIOSBootSequenceHowtoResetaCiscoRouterorSwitchtoFactoryDefaultIOSfilesBackingupIOSConfigurationFTP&TFTPCopyFileswithFTPHowtoUpgradeCiscoIOSCiscomoreCommandErasingConfigurationFilesBasicNetworkTroubleshootingNetworkTroubleshootingMethodologyandTechniquesICMP(InternetControlMessageProtocol)PingExplainedExtendedPingCommandTracerouteExplainedtracerouteCommandshowprocessesCommandIPv4RoutingWhatisIPRouting?LocalRoutesandHowtheyAppearintheRoutingTableConnected,Static,&DynamicRoutesFloatingStaticRoute-ExplanationandConfigurationDefaultStaticRouteCreateaStaticHostRouteWhatisaStaticSummaryRoute?ExplainedandConfiguredDynamicRoutingProtocolsRoutingProtocolsComparingInternalRoutingProtocols(IGPs)AdministrativeDistance&MetricEqualCostMulti-Path(ECMP)Explanation&ConfigurationUnderstandingLoopbackInterfacesandLoopbackAddressespassive-interfaceCommandInteriorGatewayProtocols(IGP)RIPOverviewAdvertiseDefaultRoutesUsingRIPConfiguringRIPv2EIGRPOverviewEIGRPDiffusingUpdateAlgorithm(DUAL)EIGRPReliableTransportProtocol(RTP)WildcardMasksWildcardMaskinEIGRPEIGRPAutomatic&ManualSummarizationEIGRPSummaryOpenShortestPathFirst(O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