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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)ACK1.4c TCPSegmentFormat1.4d UserDatagramProtocol(UDP)ConnectionlessNosessionisestablishedDoesNotGuaranteeDeliveryNosequencenumbersNoacknowledgmentsLowoverheadReliabilityIstheResponsibilityoftheApplicationDoesn’ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate1.4e UDPSegmentFormatLowoverheadNosequencenumberNoAcknowledgementnumberNowindowssizeTransportApplicationInternetNetwork1.4f PortsNumbers(1)TCPandUDPmustuseportnumberstocommunicatewiththeupperlayers.Portnumberskeeptrackofdifferentconversationscrossingthenetworksimultaneously.TFTPServerWebServer0...655350...65535TCPPorts20,21UDPPort69TCPPort80WindowsSocketsInterfaceTCPProtocolNo.6UDPProtocolNo.17IPFTPServerSMTPTCPPort25DNSUDPPort53POP3UDPPort110SNMPUDPPort1611.4g PortNumbers(2)No.below1024Well-knownportno.definedinRFC1700UsuallyindestinationporttotellthereceivinghostthepurposeoftheintendedconnectionNo.1024andaboveusedbyupperlayers(randomlychosen)tosetupsessionswithotherhostsUsedbyTCPtouseassourceanddestinationaddressesintheTCPsegmentUsuallyinSourceporttodifferentiatebetweensessionswithdifferentsourcehosts1.5 TheInternetLayerProtocolsForroutingandprovidingasinglenetworkinterfacetotheupperlayerlayers.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)TodiscovertheidentityoftheIPaddressfordisklessmachineswithaRARPbroadcastFordisklessworkstationaskingforitsIPaddress2.0 IPAddressing2.1 IPTerminology2.2 TheHierarchicalIPAddressingScheme2.3 NetworkAddressing2.4 AddressClassSummary2.5 Networkaddresses:SpecialPurposeandGuidelines2.6 AssigningNetworkAddresses2.7 AssigningHostAddressesIPAddressingwasdesignedtoallowahostononenetworktocommunicatewithahostonadifferentnetwork,regardlessofthetypeofLANsthehostareparticipatingin.2.1 IPTerminologyBit/ByteOctetNetworkAddress/SubnetAddress/HostAddressBroadcastAddressSendinginformationtoallnodesonanetworklocal/limitedbroadcast–55–allnetworks,allnodesDirectedbroadcast–allthebitsofhostaddressturnedon–allsubnetsandhostsonnetworkBroadcastdomain–agroupofdevicesreceivingbroadcastframesinitiatingfromanydevicewithinthegroup.Becausetheydonotforwardbroadcastframes,broadcastdomainsaregenerallysurroundedbyrouters.2.2 TheHierarchicalIPAddressingSchemeNetworkIDHostID32Bitsw.x.

y.z.172.16.30.56Example:ClassBTheIPaddressisastructureorhierarchicaladdresswhichconsistsofa32-bitbinarynumberof4octetsandisusuallydisplayedinthedecimalformat6(dotteddecimalnotation).2.3 NetworkAddressing*TheclassoftheNetworkisdeterminedbythehighorderbits*ClassDisforMulticastandClassEisreservedforResearch.ClassCClassANetworkAddressHostAddress0ClassBNetworkAddressHostAddress10NetworkAddressHostAddress11000000000 00000001 1..01111110 12601111111 12710000000 12810111111 19111000000 19211011111 2232.4 AddressClassSummaryNumberofNetworks12616,3842,097,152NumberofHostsperNetwork16,777,21465,534254ClassAClassBClassCRangeofNetworkIDs

(FirstOctet)1–126128–191192–2232.5 NetworkAddresses:SpecialPurposeandGuidelinesNetworkAddressCannotBe127127isreservedforloopbackfunctionsandself-diagnosticisreservedasaloopbackaddressNetworkIDand/orHostIDCannotBeAllBitsSetto1All1smeans“Allnetworks”,or“allnodes”255isabroadcastaddress;amessagesenttothisaddressisbroadcasttoeachmachineonthesubnet.E.g.55–sendto“allnodes”onnetwork128.255 LimitedBroadcastNetworkIDand/orHostIDCannotBeAllBitsSetto0-usedbyCiscorouterstodesignatethedefaultroute0means“thisnetworkorsegment”,or“thisnode”HostIDMustBeUniquetotheNetwork2.6 AssigningNetworkAddressesRouter123124.x.y.z192.121.73.z131.107.y.zRouter2.7 AssigningHostAddressesRouterRouter124.0.0.27124.0.0.28124.0.0.29131.107.0.27131.107.0.28131.107.0.29192.121.73.1124.0.0.1192.121.73.2131.107.0.1124.x.y.z192.121.73.z131.107.0.z1233.0 Subnetting3.1 WhatisaSubnet?3.2 WhySubnetting?3.3 ImplementingSubnetting3.4 SubnetMasks3.5 DefaultSubnetMasks3.6 PossibleSubnetMasksforClassA,B&C3.7 DefiningaSubnetMask3.8 DefiningaSubnetIDs3.9 DefiningaHostIds3.10 Example3.1 WhatisaSubnet?(1)7Subnet12Subnet21MainNetworkAsubnetisasubsectionofannetwork,definedforadministrativepurposeortocutdownonbroadcasttraffic,asallmessagesonanetworkare“heard”byallhostswhetherthemessageisforthathostornot.Messagesentfromonehosttoanotherwithinthesamesubnetdonotneedtoberouted,butmessagessentbetweenhostsindifferentsubnetsmustberouted.Subnetsareconnectedbyrouters,ordefaultgateways.3.1 WhatisaSubnet?(2)NetworkIDHostID10ExampleNetworkIDFROMISPNo.ofNetwork=1SUBNETMASKNo.ofHosts=65534(2^16-2)NetworkIDHostID10WeneedmorenetworksSubnetIDBorrowfromHostID3.1 WhatisaSubnet?(3)AfterSubnetNetworkIDbecome -Subnetmaskbecome

No.ofSubnets 254HostforperSubnet 254(2^8-2)NetworkIDHostID10SubnetIDUseall8bit11111111forSubnet254combinations(2^8-2)*Only8bitforHost*However,accordingtoRFC1812,255combinationscanbeachieved.3.1 WhatisaSubnet?(4)AfterSubnetNetworkID SubnetMask HostRange -54 -54 -54 -54……………………. -54 -54 -54TOTAL254SUBNETS254HOSTSPERSUBNET3.2 WhySubnetting?Reducednetworktraffic–smallerthenetworksmallerthebroadcastdomainsandlessnetworktrafficonthatnetworksegmentOptimizednetworkperformance–resultofreducednetworktrafficSimplifiedmanagement–easiertoidentifyandisolatenetworkproblemsinasmallergroupFacilitatedspanningoflargegeographicaldistances–sinceWANlinksareconsiderablyslowerandmoreexpensive;connectingmultiplesmallernetworksmakesthesystemmoreefficient3.3 ImplementingSubnettingDeterminetheNumberofRequiredNetworkIDsOneforeachsubnetOneforeachwide-areanetworkconnectionDeterminetheNumberofRequiredHostIDsperSubnetOneforeachTCP/IPhostOneforeachrouterinterfaceBasedontheaboverequirement,createthefollowing:DefineOneSubnetMaskBasedonRequirementsDefineaUniqueSubnetIDforEachPhysicalSegmentBasedontheSubnetMaskDefineValidHostIDsforEachSubnetBasedontheSubnetID3.4 SubnetMasksA32-bitvaluecomposedof1sand0s.The1sinthesubnetmaskrepresentthepositionsthatrefertothenetworkorsubnetaddresses.DistinguishestheNetworkIDfromtheHostIDUsedtoSpecifyWhethertheDestinationHostisLocalorRemoteIfANDedresultsofsourceanddestinationhostsmatch,thedestinationislocal3.5 DefaultSubnetMasksBitsUsedforSubnetMaskAddressClassDottedDecimalNotationClassAClassBClassC11111111 00000000 00000000 0000000011111111 11111111 00000000 0000000011111111 11111111 11111111 0000000016.200131.107.0.0255.255.131.107.w.x.IPAddressSubnetMaskNetworkIDHostID16.200y.z3.6 PossibleSubnetMasksforClassA,B&CClassC28922440485254ClassB28922440485254ClassA289224404852543.7 DefiningaSubnetMaskConverttheNumberofSegmentstoBinaryCounttheNumberofRequiredBitsConverttheRequiredNumberofBitstoDecimal

(HighOrder)123ExampleofClassBAddressNumberofSubnetsBinaryValueConverttoDecimal600000110=6(3Bits)4+2255.255.224.011111111 11111111 11100000 00000000SubnetMask3.8 DefiningSubnetIDs25525501111111111111111111000000000000000000000=000100000=3201000000=6401100000=9610000000=12810100000=16011000000=19211100000=224123224SubnetMask3.9 DefiningHostIDsSubnetIDsHostIDRangeInvalidx.y.32.1–x.y.63.254x.y.64.1–x.y.95.254x.y.96.1–x.y.127.254x.y.128.1