IPv4 - Packet Structure - Tutorialspoint

IPv4 - Packet Structure · Version − Version no. · IHL − Internet Header Length; Length of entire IP header. · DSCP − Differentiated Services Code Point; this is ... IPv4Tutorial IPv4-Home IPv4-Overview IPv4-OSIModel IPv4-TCP/IPModel IPv4-PacketStructure IPv4-Addressing IPv4-AddressClasses IPv4-Subnetting IPv4-VLSM IPv4-ReservedAddresses IPv4-Example IPv4-Summary IPv4UsefulResources IPv4-QuickGuide IPv4-UsefulResources IPv4-Discussion SelectedReading UPSCIASExamsNotes Developer'sBestPractices QuestionsandAnswers EffectiveResumeWriting HRInterviewQuestions ComputerGlossary WhoisWho IPv4-PacketStructure Advertisements PreviousPage NextPage  InternetProtocolbeingalayer-3protocol(OSI)takesdataSegmentsfromlayer-4(Transport)anddividesitintopackets.IPpacketencapsulatesdataunitreceivedfromabovelayerandaddtoitsownheaderinformation. TheencapsulateddataisreferredtoasIPPayload.IPheadercontainsallthenecessaryinformationtodeliverthepacketattheotherend. IPheaderincludesmanyrelevantinformationincludingVersionNumber,which,inthiscontext,is4.Otherdetailsareasfollows− Version−Versionno.ofInternetProtocolused(e.g.IPv4). IHL−InternetHeaderLength;LengthofentireIPheader. DSCP−DifferentiatedServicesCodePoint;thisisTypeofService. ECN−ExplicitCongestionNotification;Itcarriesinformationaboutthecongestionseenintheroute. TotalLength−LengthofentireIPPacket(includingIPheaderandIPPayload). Identification−IfIPpacketisfragmentedduringthetransmission,allthefragmentscontainsameidentificationnumber.toidentifyoriginalIPpackettheybelongto. Flags−Asrequiredbythenetworkresources,ifIPPacketistoolargetohandle,these‘flags’tellsiftheycanbefragmentedornot.Inthis3-bitflag,theMSBisalwayssetto‘0’. FragmentOffset−ThisoffsettellstheexactpositionofthefragmentintheoriginalIPPacket. TimetoLive−Toavoidloopinginthenetwork,everypacketissentwithsomeTTLvalueset,whichtellsthenetworkhowmanyrouters(hops)thispacketcancross.Ateachhop,itsvalueisdecrementedbyoneandwhenthevaluereacheszero,thepacketisdiscarded. Protocol−TellstheNetworklayeratthedestinationhost,towhichProtocolthispacketbelongsto,i.e.thenextlevelProtocol.ForexampleprotocolnumberofICMPis1,TCPis6andUDPis17. HeaderChecksum−Thisfieldisusedtokeepchecksumvalueofentireheaderwhichisthenusedtocheckifthepacketisreceivederror-free. SourceAddress−32-bitaddressoftheSender(orsource)ofthepacket. DestinationAddress−32-bitaddressoftheReceiver(ordestination)ofthepacket. Options−Thisisoptionalfield,whichisusedifthevalueofIHLisgreaterthan5.TheseoptionsmaycontainvaluesforoptionssuchasSecurity,RecordRoute,TimeStamp,etc. UsefulVideoCourses Video CiscoCCNA:TheA,B,C'sofIPv6 15Lectures 3.5hours LazaroDiaz MoreDetail Video IPv6:InternetProtocolversion6 29Lectures 4hours TELCOMAGlobal MoreDetail Video IPv4SubnettingforAbsoluteBeginners 30Lectures 2hours NabilMEKHALLET MoreDetail PreviousPage PrintPage NextPage  Advertisements Print  AddNotes  Bookmarkthispage  ReportError  Suggestions Save Close Dashboard Logout