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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.17IPFTPServerSMTPTCPPort25DNSUDPPort53POP3UDPPort110SNMPUDPPort1611.4g PortNumbers(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...4IPAddress=8HardwareAddress=08004...IPAddress=9HardwareAddress=08007...3HardwareAddress=08007...21ping9ARPBroadcast1.5f ResolvingaRemoteIPAddressARouterBIPAddress=4HardwareAddress=08004...IPAddress=9HardwareAddress=08009...ARPCache08009...08006...ARPCache08004...4108005...08006...25ping9ARPCache3Network1Network2321ARPBroadcastforRouterInterfaceAARPBroadcastforRouterInterfaceBAB451.5g ReverseAddressResolutionProtocol(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.6Example:ClassBTheIPaddressisastructureorhierarchicaladdresswhichconsistsofa32-bitbinarynumberof4octetsandisusuallydisplayedinthedecimalformat6(dotteddecimalnotation).2.3NetworkAddressing*TheclassoftheNetworkisdeterminedbythehighorderbits*ClassDisforMulticastandClassEisreservedforResearch.ClassCClassANetworkAddressHostAddress0ClassBNetworkAddressHostAddress10NetworkAddressHostAddress11000000000000000011..0111111012601111111127100000001281011111119111000000192110111112232.4AddressClassSummaryNumberofNetworks12616,3842,097,152NumberofHostsperNetwork16,777,21465,534254ClassAClassBClassCRangeofNetworkIDs

(FirstOctet)1–126128–191192–2232.5NetworkAddresses:SpecialPurposeandGuidelinesNetworkAddressCannotBe127127isreservedforloopbackfunctionsandself-diagnosticisreservedasaloopbackaddressNetworkIDand/orHostIDCannotBeAllBitsSetto1All1smeans“Allnetworks”,or“allnodes”255isabroadcastaddress;amessagesenttothisaddressisbroadcasttoeachmachineonthesubnet.E.g.55–sendto“allnodes”onnetwork128.255LimitedBroadcastNetworkIDand/orHostIDCannotBeAllBitsSetto0-usedbyCiscorouterstodesignatethedefaultroute0means“thisnetworkorsegment”,or“thisnode”HostIDMustBeUniquetotheNetwork2.6AssigningNetworkAddressesRouter123124.x.y.z192.121.73.z131.107.y.zRouter2.7AssigningHostAddressesRouterRouter789789124.x.y.z192.121.73.z131.107.0.z1233.0Subnetting3.1WhatisaSubnet?3.2 WhySubnetting?3.3 ImplementingSubnetting3.4 SubnetMasks3.5 DefaultSubnetMasks3.6 PossibleSubnetMasksforClassA,B&C3.7 DefiningaSubnetMask3.8 DefiningaSubnetIDs3.9 DefiningaHostIds3.10Example3.1WhatisaSubnet?(1)7Subnet12Subnet21MainNetworkAsubnetisasubsectionofannetwork,definedforadministrativepurposeortocutdownonbroadcasttraffic,asallmessagesonanetworkare““heard”byallhostswhetherthemessageisforthathostornot.Messagesentfromonehosttoanotherwithinthesamesubnetdonotneedtoberouted,butmessagessentbetweenhostsindifferentsubnetsmustberouted.Subnetsareconnectedbyrouters,ordefaultgateways.3.1WhatisaSubnet?(2)NetworkIDHostID10ExampleNetworkIDFROMISPNo.ofNetwork=1SUBNETMASKNo.ofHosts=65534(2^16-2)NetworkIDHostID10WeneedmorenetworksSubnetIDBorrowfromHostID3.1WhatisaSubnet?(3)AfterSubnetNetworkIDbecome-SubnetmaskbecomeNo.ofSubnets254HostforperSubnet254(2^8-2)NetworkIDHostID10SubnetIDUseall8bit11111111forSubnet254combinations(2^8-2)*Only8bitforHost*However,accordingtoRFC1812,255combinationscanbeachieved.3.1WhatisaSubnet?(4)AfterSubnetNetworkIDSubnetMaskHostRange-54-54-54-54………………………….-54-54-54TOTAL254SUBNETS254HOSTSPERSUBNET3.2WhySubnetting?Reducednetworktraffic––smallerthenetworksmallerthebroadcastdomainsandlessnetworktrafficonthatnetworksegmentOptimizednetworkperformance––resultofreducednetworktrafficSimplifiedmanagement––easiertoidentifyandisolatenetworkproblemsinasmallergroupFacilitatedspanningoflargegeographicaldistances––sinceWANlinksareconsiderablyslowerandmoreexpensive;connectingmultiplesmallernetworksmakesthesystemmoreefficient3.3ImplementingSubnettingDeterminetheNumberofRequiredNetworkIDsOneforeachsubnetOneforeachwide-areanetworkconnectionDeterminetheNumberofRequiredHostIDsperSubnetOneforeachTCP/IPhostOneforeachrouterinterfaceBasedontheaboverequirement,createthefollowing:DefineOneSubnetMaskBasedonRequirementsDefineaUniqueSubnetIDforEachPhysicalSegmentBasedontheSubnetMaskDefineValidHostIDsforEachSubnetBasedontheSubnetID3.4SubnetMasksA32-bitvaluecomposedof1sand0s.The1sinthesubnetmaskrepresentthepositionsthatrefertothenetworkorsubnetaddresses.DistinguishestheNetworkIDfromtheHostIDUsedtoSpecifyWhethertheDestinationHostisLocalorRemoteIfANDedresultsofsourceanddestinationhostsmatch,thedestinationislocal3.5DefaultSubnetMasksBitsUsedforSubnetMaskAddressClassDottedDecimalNotationClassAClassBClassC11111111000000000000000000000000111111111111111100000000000000001111111111111111111111110000000016.20007.w.x.IPAddressSubnetMaskNetworkIDHostID16.200y.z3.6PossibleSubnetMasksforClassA,B&CClassC28922440485254ClassB28922440485254ClassA289224404852543.7DefiningaSubnetMaskConverttheNumberofSegmentstoBinaryCounttheNumberofRequiredBitsConverttheRequired