互联网协议英文.ppt

InternetProtocol Overview 1 0TCP IPandtheDoDModel2 0IPAddressing3 0Subnetting 1 0TCP IPandtheDoDModel 1 1ComparisonofDodandOSIModel1 2TheTCP IPprotocolsuite1 3TheProcess ApplicationlayerProtocols1 4TheHost to HostLayerProtocols1 5TheInternetLayerProtocols 1 1ComparisonofDoDandOSIModel 1 TheTCP IPsuitewascreatedbytheDoDTheDoDmodelisacondensedversionoftheOSImodel Application Presentation Session Transport Network DataLink Physical Process Application Host to Host Internet NetworkAccess DoDModel OSIModel Node to nodeapplicationcommunicationControlsuser interfacespecifications Settinguptheleveloftransmissionserviceforapplications TakescareIPaddressanddesignateprotocolsforlogicaltransmissionofpacketsovertheentirenetwork Overseeshardwareaddressinganddefinesprotocolsforthephysicaltransmissionofdata 1 1ComparisonofDoDandOSIModel 2 TCP IPModel OSIModel 1 2TheTCP IPProtocolSuite Process Application Telnet TCP UDP IP ICMP ARP LANTechnologies Ethernet FastEthernet TokenRing FDDI WANTechnologies SerialLines FrameRelay ATM RARP Host to Host Internet NetworkAccess FTP TFTP SMTP LPD SNMP NFS XWindow BootP DHCP DNS IGMP 1 3TheProcess ApplicationLayerProtocols Telnet TelephoneNetworkFTP FileTransferProtocolTFTP TrivialFileTransferProtocolNFS NetworkFileSystemSMTP SimpleMailTransferProtocolLPD LinePrinterDaemonXWindow writingaGUI basedclient serverapplicationsDNS DomainNameService DNS BootP BootstrapProtocolDHCP DynamicHostConfigurationProtocol 1 4TheHost to HostLayerProtocols Toshieldtheupper layerapplicationsfromthecomplexitiesofthenetworkTCP TransmissionControlProtocol BreakdowndatafromupperlayersintoSegmentNumbersandsequenceseachsegmentConnection oriented virtualcircuitrequiredUserDatagramProtocol UDP BreakdowndatabutnotsequencethesegmentThinprotocolwhichdoesn ttakeupmuchbandwidthonanetworkConnectionless novirtualcircuitrequired thusunreliableForsendinglittlemessageandreliabilityaccomplishedattheupperlayers 1 4aTransmissionControlProtocol TCP Connection orientedSessionisestablishedbeforeexchangingdataVirtualcircuitrequiredReliableDeliverySequencenumbersAcknowledgments ACKs Doesn ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate 1 4bTCPThree WayHandshake Application Transport Internet Network Data Application Transport Internet Network Data ACK startbyte ACK 1 4cTCPSegmentFormat 1 4dUserDatagramProtocol UDP ConnectionlessNosessionisestablishedDoesNotGuaranteeDeliveryNosequencenumbersNoacknowledgmentsLowoverheadReliabilityIstheResponsibilityoftheApplicationDoesn ttrustthelowerlayersandrunsitsownCRCUsesPortNumbersasEndpointstoCommunicate 1 4eUDPSegmentFormat LowoverheadNosequencenumberNoAcknowledgementnumberNowindowssize Transport Application Internet Network 1 4fPortsNumbers 1 TCPandUDPmustuseportnumberstocommunicatewiththeupperlayers Portnumberskeeptrackofdifferentconversationscrossingthenetworksimultaneously 0 65535 0 65535 TCPPorts20 21 UDPPort69 TCPPort80 WindowsSocketsInterface TCPProtocolNo 6 UDPProtocolNo 17 IP TCPPort25 UDPPort53 UDPPort110 UDPPort161 1 4gPortNumbers 2 No below1024Well knownportno definedinRFC1700UsuallyindestinationporttotellthereceivinghostthepurposeoftheintendedconnectionNo 1024andaboveusedbyupperlayers randomlychosen tosetupsessionswithotherhostsUsedbyTCPtouseassourceanddestinationaddressesintheTCPsegmentUsuallyinSourceporttodifferentiatebetweensessionswithdifferentsourcehosts 1 5TheInternetLayerProtocols Forroutingandprovidingasinglenetworkinterfacetotheupperlayerlayers AllnetworkpathsthroughthemodelgothroughIP ProtocolsworksattheInternetLayer InternetProtocol IP essentiallyistheInternetLayer andotherprotocolsfoundheremerelyexisttosupportit InternetControlMessageProtocol ICMP AddressResolutionProtocol ARP ReverseAddressResolutionProtocol RARP 1 5aInternetProtocol IP AddressesandRoutesPacketsaccordingtotheRoutingTableFragmentsandReassemblesDatagrams PacketsConnectionlessNosessionisestablishedNonguaranteed BestEffort DeliveryReliabilityIstheResponsibilityofHigher LayerProtocolsandApplications 1 5bIPheader Protocolnumber 01 ICMP 06 TCP 17 UDP etc 1 5cInternetControlMessageProtocol ICMP ManagementProtocolandmessagingserviceproviderforIP Inroutersolicitation ICMPisusedtosendthefollowingeventsandmessages intheDataarea DestinationUnreachableBufferFullHopsPingTraceroute 1 5dAddressResolutionProtocol ARP SuccessfulMappingofanIPAddresstoaHardwareAddressARPUsesaLocalBroadcasttoObtainaHardwareAddressAddressMappingsAreStoredinaCacheforFutureReference 1 5eResolvingalocalIPAddress ARPCache 150 107 7 2808004 ARPCache 150 107 7 2808004 4 IPAddress 150 107 7 28HardwareAddress 08004 IPAddress 150 107 7 29HardwareAddress 08007 3 HardwareAddress 08007 2 1 ping150 107 7 29 ARPBroadcast 1 5fResolvingaRemoteIPAddress IPAddress 150 107 3 24HardwareAddress 08004 IPAddress 150 107 7 29HardwareAddress 08009 ARPCache 150 107 7 708009 150 107 7 108006 ARPCache 150 107 3 708004 4 1 150 107 3 108005 150 107 7 108006 2 5 ping150 107 7 29 ARPCache 3 Network1 Network2 3 2 1 ARPBroadcastforRouterInterfaceA ARPBroadcastforRouterInterfaceB A B 4 5 1 5gReverseAddressResolutionProtocol RARP TodiscovertheidentityoftheIPaddressfordisklessmachineswithaRARPbroadcastFordisklessworkstationaskingforitsIPaddress 2 0IPAddressing 2 1IPTerminology2 2TheHierarchicalIPAddressingScheme2 3NetworkAddressing2 4AddressClassSummary2 5Networkaddresses SpecialPurposeandGuidelines2 6AssigningNetworkAddresses2 7AssigningHostAddresses IPAddressingwasdesignedtoallowahostononenetworktocommunicatewithahostonadifferentnetwork regardlessofthetypeofLANsthehostareparticipatingin 2 1IPTerminology Bit ByteOctetNetworkAddress SubnetAddress HostAddressBroadcastAddressSendinginformationtoallnodesonanetworklocal limitedbroadcast 255 255 255 255 allnetworks allnodesDirectedbroadcast allthebitsofhostaddressturnedon allsubnetsandhostsonnetworkBroadcastdomain agroupofdevicesreceivingbroadcastframesinitiatingfromanydevicewithinthegroup Becausetheydonotforwardbroadcastframes broadcastdomainsaregenerallysurroundedbyrouters 2 2TheHierarchicalIPAddressingScheme NetworkID HostID 32Bits w x y z 172 16 30 56 Example ClassB TheIPaddressisastructureorhierarchicaladdresswhichconsistsofa32 bitbinarynumberof4octetsandisusuallydisplayedinthedecimalformat172 16 30 56 dotteddecimalnotation 2 3NetworkAddressing TheclassoftheNetworkisdeterminedbythehighorderbits ClassDisforMulticastandClassEisreservedforResearch ClassC ClassA NetworkAddress HostAddress 0 ClassB NetworkAddress HostAddress 10 NetworkAddress HostAddress 110 00000000000000011 0111111012601111111127 1000000012810111111191 1100000019211011111223 2 4AddressClassSummary NumberofNetworks 126 16 384 2 097 152 NumberofHostsperNetwork 16 777 214 65 534 254 ClassA ClassB ClassC RangeofNetworkIDs FirstOctet 1 126 128 191 192 223 2 5NetworkAddresses SpecialPurposeandGuidelines NetworkAddressCannotBe127127isreservedforloopbackfunctionsandself diagnostic127 0 0 1isreservedasaloopbackaddressNetworkIDand orHostIDCannotBeAllBitsSetto1All1smeans Allnetworks or allnodes 255isabroadcastaddress amessagesenttothisaddressisbroadcasttoeachmachineonthesubnet E g 128 2 255 255 sendto allnodes onnetwork128 2255 255 255 255LimitedBroadcastNetworkIDand orHostIDCannotBeAllBitsSetto00 0 0 0 usedbyCiscorouterstodesignatethedefaultroute0means thisnetworkorsegment or thisnode HostIDMustBeUniquetotheNetwork 2 6AssigningNetworkAddresses 1 2 3 124 x y z 192 121 73 z 131 107 y z 2 7AssigningHostAddresses 124 0 0 27 124 0 0 28 124 0 0 29 131 107 0 27 131 107 0 28 131 107 0 29 192 121 73 1 124 0 0 1 192 121 73 2 131 107 0 1 124 x y z 192 121 73 z 131 107 0 z 1 2 3 3 0Subnetting 3 1WhatisaSubnet 3 2WhySubnetting 3 3ImplementingSubnetting3 4SubnetMasks3 5DefaultSubnetMasks3 6PossibleSubnetMasksforClassA B C3 7DefiningaSubnetMask3 8DefiningaSubnetIDs3 9DefiningaHostIds3 10Example 3 1WhatisaSubnet 1 Asubnetisasubsectionofannetwork definedforadministrativepurposeortocutdownonbroadcasttraffic asallmessagesonanetworkare heard byallhostswhetherthemessageisforthathostornot Messagesentfromonehosttoanotherwithinthesamesubnetdonotneedtoberouted butmessagessentbetweenhostsindifferentsubnetsmustberouted Subnetsareconnectedbyrouters ordefaultgateways 3 1WhatisaSubnet 2 NetworkID HostID 1 0 ExampleNetworkIDFROMISP131 107 0 0No ofNetwork 1SUBNETMASK255 255 0 0No ofHosts 65534 2 16 2 NetworkID HostID 1 0 Weneedmorenetworks SubnetID BorrowfromHostID 3 1WhatisaSubnet 3 AfterSubnetNetworkIDbecome131 107 1 0 131 107 254 0Subnetmaskbecome255 255 255 0No ofSubnets254HostforperSubnet254 2 8 2 NetworkID HostID 1 0 SubnetID Useall8bit11111111forSubnet254combinations 2 8 2 Only8bitforHost However accordingtoRFC1812 255combinationscanbeachieved 3 1WhatisaSubnet 4 AfterSubnetNetworkIDSubnetMaskHostRange131 107 1 0255 255 255 0131 107 1 1 131 107 1 254131 107 2 0255 255 255 0131 107 2 1 131 107 2 254131 107 3 0255 255 255 0131 107 3 1 131 107 3 254131 107 4 0255 255 255 0131 107 4 1 131 107 4 254 131 107 252 0255 255 255 0131 107 252 1 131 107 252 254131 107 253 0255 255 255 0131 107 253 1 131 107 253 254131 107 254 0255 255 255 0131 107 254 1 131 107 254 254TOTAL254SUBNETS254HOSTSPERSUBNET 3 2WhySubnetting Reducednetworktraffic smallerthenetworksmallerthebroadcastdomainsandlessnetworktrafficonthatnetworksegmentOptimizednetworkperformance resultofreducednetworktrafficSimplifiedmanagement easiertoidentifyandisolatenetworkproblemsinasmallergroupFacilitatedspanningoflargegeographicaldistances sinceWANlinksareconsiderablyslowerandmoreexpensive connectingmultiplesmallernetworksmakesthesystemmoreefficient 3 3ImplementingSubnetting DeterminetheNumberofRequiredNetworkIDsOneforeachsubnetOneforeachwide areanetworkconnectionDeterminetheNumberofRequiredHostIDsperSubnetOneforeachTCP IPhostOneforeachrouterinterfaceBasedontheaboverequirement createthefollowing DefineOneSubnetMaskBasedonRequirementsDefineaUniqueSubnetIDforEachPhysicalSegmentBasedontheSubnetMaskDefineValidHostIDsforEachSubnetBasedontheSubnetID 3 4SubnetMasks A32 bitvaluecomposedof1sand0s The1sinthesubnetmaskrepresentthepositionsthatrefertothenetworkorsubnetaddresses DistinguishestheNetworkIDfromtheHostIDUsedtoSpecifyWhethertheDestinationHostisLocalorRemoteIfANDedresultsofsourceanddestinationhostsmatch thedestinationislocal 3 5DefaultSubnetMasks BitsUsedforSubnetMask AddressClass DottedDecimalNotation ClassAClassBClassC 111111110000000000000000000000001111111111111111000000000000000011111111111111111111111100000000 255 0 0 0255 255 0 0255 255 255 0 131 107 w x IPAddress SubnetMask NetworkID HostID 16 200 y z 3 6PossibleSubnetMasksforClassA B C ClassC255 255 255 128255 255 255 192255 255 255 224255 255 255 240255 255 255 248255 255 255 252255 255 255 254 ClassB255 255 128 0255 255 192 0255 255 224 0255 255 240 0255 255 248 0255 255 252 0255 255 254 0255 255 255 0255 255 255 128255 255 255 192255 255 255 224255 255 255 240255 255 255 248255 255 255 252255 255 255 254 ClassA255 128 0 0255 192 0 0255 224 0 0255 240 0 0255 248 0 0255 252 0 0255 254 0 0255 255 0 0255 255 128 0255 255 192 0255 255 224 0255 255 240 0255 255 248 0255 255 252 0255 255 254 0255 255 255 0 255 255 255 128255 255 255 192255 255 255 224255 255 255 240255 255 255 248255 255 255 252255 255 255 254 3 7DefiningaSubnetMask ConverttheNumberofSegmentstoBinaryCounttheNumberofRequiredBitsConverttheRequiredNumberofBitstoDecimal HighOrder 1 2 3 Ex