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InternetProtocolOverview1.0 TCP/IPandtheDoDModel2.0 IPAddressing3.0 Subnetting1.0 TCP/IPandtheDoDModel1.1 ComparisonofDodandOSIModel1.2 TheTCP/IPprotocolsuite1.3 TheProcess/ApplicationlayerProtocols1.4 TheHost-to-HostLayerProtocols1.5 TheInternetLayerProtocols1.1 ComparisonofDoDandOSIModel(1)TheTCP/IPsuitewascreatedbytheDoDTheDoDmodelisacondensedversionoftheOSImodelApplicationPresentationSessionTransportNetworkDataLinkPhysicalProcess/ApplicationHost-to-HostInternetNetworkAccessDoDModelOSIModelNode-to-nodeapplicationcommunicationControlsuser-interfacespecificationsSettinguptheleveloftransmissionserviceforapplicationsTakescareIPaddressanddesignateprotocolsforlogicaltransmissionofpacketsovertheentirenetworkOverseeshardwareaddressinganddefinesprotocolsforthephysicaltransmissionofdata1.1 ComparisonofDoDandOSIModel(2)TCP/IPModelOSIModel1.2 TheTCP/IPProtocolSuiteProcess/ApplicationTelnetTCPUDPIPICMPARPLANTechnologies:Ethernet,FastEthernet,TokenRing,FDDIWANTechnologies:SerialLines,FrameRelay,ATMRARPHost-to-HostInternetNetworkAccessFTPTFTPSMTPLPDSNMPNFSXWindowBootP/DHCPDNSIGMP1.3 TheProcess/ApplicationLayerProtocolsTelnet–TelephoneNetworkFTP–FileTransferProtocolTFTP–TrivialFileTransferProtocolNFS–NetworkFileSystemSMTP–SimpleMailTransferProtocolLPD–LinePrinterDaemonXWindow–writingaGUI-basedclient/serverapplicationsDNS–DomainNameService(DNS)BootP–BootstrapProtocolDHCP–DynamicHostConfigurationProtocol1.4 TheHost-to-HostLayerProtocolsToshieldtheupper-layerapplicationsfromthecomplexitiesofthenetworkTCP(TransmissionControlProtocol)BreakdowndatafromupperlayersintoSegmentNumbersandsequenceseachsegmentConnection-oriented–virtualcircuitrequiredUserDatagramProtocol(UDP)BreakdowndatabutnotsequencethesegmentThinprotocolwhichdoesn’ttakeupmuchbandwidthonanetworkConnectionless–novirtualcircuitrequired,thusunreliableForsendinglittlemessageandreliabilityaccomplishedattheupperlayers1.4a TransmissionControlProtocol(TCP)Connection-orientedSessionisestablishedbeforeexchangingdataVirtualcircuitrequiredReliableDeliverySequencenumbersAcknowledgments(ACKs)Doesn’ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate1.4b TCPThree-WayHandshakeApplicationTransportInternetNetworkDataApplicationTransportInternetNetworkData,ACK(+startbyte)ACK1.4cTCPSegmentFormat1.4dUserDatagramProtocol(UDP)ConnectionlessNosessionisestablishedDoesNotGuaranteeDeliveryNosequencenumbersNoacknowledgmentsLowoverheadReliabilityIstheResponsibilityoftheApplicationDoesn’’ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate1.4eUDPSegmentFormatLowoverheadNosequencenumberNoAcknowledgementnumberNowindowssizeTransportApplicationInternetNetwork1.4fPortsNumbers(1)TCPandUDPmustuseportnumberstocommunicatewiththeupperlayers.Portnumberskeeptrackofdifferentconversationscrossingthenetworksimultaneously.TFTPServerWebServer0...655350...65535TCPPorts20,21UDPPort69TCPPort80WindowsSocketsInterfaceTCPProtocolNo.6UDPProtocolNo.17IPFTPServerSMTPTCPPort25DNSUDPPort53POP3UDPPort110SNMPUDPPort1611.4gPortNumbers(2)No.below1024Well-knownportno.definedinRFC1700UsuallyindestinationporttotellthereceivinghostthepurposeoftheintendedconnectionNo.1024andaboveusedbyupperlayers(randomlychosen)tosetupsessionswithotherhostsUsedbyTCPtouseassourceanddestinationaddressesintheTCPsegmentUsuallyinSourceporttodifferentiatebetweensessionswithdifferentsourcehosts1.5TheInternetLayerProtocolsForroutingandprovidingasinglenetworkinterfacetotheupperlayerlayers.AllnetworkpathsthroughthemodelgothroughIP.ProtocolsworksattheInternetLayer:InternetProtocol(IP)–essentiallyistheInternetLayer,andotherprotocolsfoundheremerelyexisttosupportit.InternetControlMessageProtocol(ICMP)AddressResolutionProtocol(ARP)ReverseAddressResolutionProtocol(RARP)1.5a InternetProtocol(IP)AddressesandRoutesPacketsaccordingtotheRoutingTableFragmentsandReassemblesDatagrams/PacketsConnectionlessNosessionisestablishedNonguaranteed“BestEffort”DeliveryReliabilityIstheResponsibilityofHigher-LayerProtocolsandApplications1.5b IPheader*Protocolnumber:01–ICMP,06––TCP,17–UDP,etc.1.5c InternetControlMessageProtocol(ICMP)ManagementProtocolandmessagingserviceproviderforIP.Inroutersolicitation,ICMPisusedtosendthefollowingeventsandmessages(intheDataarea):DestinationUnreachableBufferFullHopsPingTraceroute1.5d AddressResolutionProtocol(ARP)SuccessfulMappingofanIPAddresstoaHardwareAddressARPUsesaLocalBroadcasttoObtainaHardwareAddressAddressMappingsAreStoredinaCacheforFutureReference1.5e ResolvingalocalIPAddressARPCache808004...ARPCache808004...4HardwareAddress=08004...HardwareAddress=08007...3HardwareAddress=08007...21pingARPBroadcast1.5f ResolvingaRemoteIPAddressARouterBHardwareAddress=08004...HardwareAddress=08009...ARPCache08009...08006...ARPCache08004...4108005...08006...25ARPCache3Network1Network2321ARPBroadcastforRouterInterfaceAARPBroadcastforRouterInterfaceBAB451.5gReverseAddressResolutionProtocol(RARP)TodiscovertheidentityoftheIPaddressfordisklessmachineswithaRARPbroadcastFordisklessworkstationaskingforitsIPaddress2.0IPAddressing2.1IPTerminology2.2TheHierarchicalIPAddressingScheme2.3NetworkAddressing2.4AddressClassSummary2.5Networkaddresses:SpecialPurposeandGuidelines2.6AssigningNetworkAddresses2.7AssigningHostAddressesIPAddressingwasdesignedtoallowahostononenetworktocommunicatewithahostonadifferentnetwork,regardlessofthetypeofLANsthehostareparticipatingin.2.1IPTerminologyBit/ByteOctetNetworkAddress/SubnetAddress/HostAddressBroadcastAddressSendinginformationtoallnodesonanetworklocal/limitedbroadcast–55––allnetworks,allnodesDirectedbroadcast––allthebitsofhostaddressturnedon––allsubnetsandhostsonnetworkBroadcastdomain––agroupofdevicesreceivingbroadcastframesinitiatingfromanydevicewithinthegroup.Becausetheydonotforwardbroadcastframes,broadcastdomainsaregenerallysurroundedbyrouters.2.2TheHierarchicalIPAddressingSchemeNetworkIDHostID32Bitsw.x.y.z.Example:ClassBTheIPaddressisastructureorhierarchicaladdresswhichconsistsofa32-bitbinarynumberof4octetsandisusuallydisplayedinthedecimalformat6(dotteddecimalnotation).2.3NetworkAddressing*TheclassoftheNetworkisdeterminedbythehighorderbits*ClassDisforMulticastandClassEisreservedforResearch.ClassCClassANetworkAddressHostAddress0ClassBNetworkAddressHostAddress10NetworkAddressHostAddress11000000000000000011..2.4AddressClassSummaryNumberofNetworks12616,3842,097,152NumberofHostsperNetwork16,777,21465,534254ClassAClassBClassCRangeofNetworkIDs(FirstOctet)1––126128––191192––2232.5NetworkAddresses:SpecialPurposeandGuidelinesNetworkAddressCannotBe127127isreservedforloopbackfunctionsandself-diagnosticNetworkIDand/orHostIDCannotBeAllBitsSetto1All1smeans““Allnetworks””,or““allnodes””255isabroadcastaddress;amessagesenttothisaddressisbroadcasttoeachmachineonthesubnet.E.g.55––sendto““allnodes””onnetwork128.2NetworkIDand/orHostIDCannotBeAllBitsSetto00means““thisnetworkorsegment””,or““thisnode””HostIDMustBeUniquetotheNetwork2.6AssigningNetworkAddressesRouter123124.x.y.z192.121.73.z131.107.y.zRouter2.7AssigningHostAddressesRouterRouter124.x.y.z192.121.73.z131.107.0.z1233.0Subnetting3.1WhatisaSubnet?3.2WhySubnetting?3.3ImplementingSubnetting3.4SubnetMasks3.5DefaultSubnetMasks3.6PossibleSubnetMasksforClassA,B&C3.7DefiningaSubnetMask3.8DefiningaSubnetIDs3.9DefiningaHostIds3.10Example3.1WhatisaSubnet?(1)7Subnet12Subnet21MainNetworkAsubnetisasubsectionofannetwork,definedforadministrativepurposeortocutdownonbroadcasttraffic,asallmessagesonanetworkare““heard”byallhostswhetherthemessageisforthathostornot.Messagesentfromonehosttoanotherwithinthesamesubnetdonotneedtoberouted,butmessagessentbetweenhostsindifferentsubnetsmustberouted.Subnetsareconnectedbyrouters,ordefaultgateways.3.1WhatisaSubnet?(2)NetworkIDHostID10ExampleNetworkIDFROMISPNo.ofNetwork=1SUBNETMASKNo.ofHosts=65534(2^16-2)NetworkIDHostID10WeneedmorenetworksSubnetIDBorrowfromHostID3.1WhatisaSubnet?(3)AfterSubnetNetworkIDbecomeSubnetmaskbecomeNo.ofSubnets254HostforperSubnet254(2^8-2)NetworkIDHostID10SubnetIDUseall8bit11111111forSubnet254combinations(2^8-2)*Only8bitforHost*However,accordingtoRFC1812,255combinationscanbeachieved.3.1WhatisaSubnet?(4)AfterSubnetNetworkID SubnetMaskHostRange…………………….TOTAL254SUBNETS254HOSTSPERSUBNET3.2WhySubnetting?Reducednetworktraffic––smallerthenetworksmallerthebroadcastdomainsandlessnetworktrafficonthatnetworksegmentOptimizednetworkperformance–resultofreducednetworktrafficSimplifiedmanagement–easiertoidentifyandisolatenetworkproblemsinasmallergroupFacilitatedspanningoflargegeographicaldistances––sinceWANlinksareconsiderablyslowerandmoreexpensive;connectingmultiplesmallernetworksmakesthesystemmoreefficient3.3ImplementingSubnettingDeterminetheNumberofRequiredNetworkIDsOneforeachsubnetOneforeachwide-areanetworkconnectionDeterminetheNumberofRequiredHostIDsperSubnetOneforeachTCP/IPhostOneforeachrouterinterfaceBasedontheaboverequirement,createthefollowing:DefineOneSubnetMaskBasedonRequirementsDefineaUniqueSubnetIDforEachPhysicalSegmentBasedontheSubnetMaskDefineValidHostIDsforEachSubnetBasedontheSubnetID3.4SubnetMasksA32-bitvaluecomposedof1sand0s.The1sinthesubnetmaskrepresentthepositionsthatrefertothenetworkorsubnetaddresses.DistinguishestheNetworkIDfromtheHostIDUsedtoSpecifyWhethertheDestinationHostisLocalorRemoteIfANDedresultsofsourceanddestinationhostsmatch,thedestinationislocal3.5DefaultSubnetMasksBitsUsedforSubnetMaskAddressClassDottedDecimalNotationClassAClassBClassC16.20007.w.x.IPAddressSubnetMaskNetworkIDHostID16.200y.z3.6PossibleSubnetMasksforClassA,B&CClassCClassBClassA3.7DefiningaSubnetMaskConverttheNumberofSegmentstoBinaryCounttheNumbero