ch26-Limitation-of-Basic-Mobile-IP-移动IP技术-教学课件

LimitationofBasicMobileIPLimitationofBasicMobileIP1LimitationofBasicMobileIPMobileIPsupportsmobilityacrossbothhomogeneousandheterogeneoussystems.Itiswellsuitedformacromobilitymanagement,butlesssuitedformicromobilitymanagement.LimitationofBasicMobileIPM2LimitationofBasicMobileIPNon-optimalroutingallpacketsareroutedtoHomeAgentHandoffsnoprovisionsforforwardingin-flightdatagramsarelostSecurityandQoSLimitationofBasicMobileIP3Limitation1

IETFRouteOptimizationTriangularroutingproblem

PacketssentfromaCNtoanMNarefirstinterceptedbytheHAandthentunneledtotheMN.However,packetsfromtheMNaresentdirectlytotheCN.Thistriangularroutingproblemresultsincommunicationroutessignificantlylongerthantheoptimalroutesandintroducesextradelayforpacketdelivery.OptimalRoutingallowscorrespondingnodestokeepcare-ofaddressbindingsCN->MNroutingcanthenbeoptimalproblem:howtoupdateCNsCannotregisterwithallCNsLimitation1

IETFRouteOptimi4Limitation2

HandoffManagementinMIPWhenanMNmovesfromonesubnettoanother,thehandoffprocedureiscarriedoutbythefollowingsteps:TheMNobtainsanewCoAwhenitentersanewsubnet.TheMNregistersthenewCoAwithitsHA.TheHAsetsupanewtunneluptotheendpointofthenewCoAandremovesthetunneltotheoldCoA.Oncethenewtunnelissetup,theHAtunnelspacketsdestinedtotheMNusingtheMN’snewCoA.Limitation2

HandoffManagemen5HandoffdatagramsarelostWhenanMNmovesfromonesubnettoanother,thenewFAcannotinformtheoldFAaboutthemovementoftheMN.Hence,packetsalreadytunneledtotheoldCoAandinflightarelost.RegistrationfollowsdirectorindirectproceduresForwardingallowsFAstoforwarddatagramstoMNsthathavemovedIn-flightdatagramsoldFAhasnoforwardinginformationdatagramsarelostHandoffdatagramsarelostWhen6MobileIPisnotasatisfactorysolutionforhighlymobileusersMobileIPrequiresanMNtosendalocationupdatetoitsHAwheneveritmovesfromonesubnettoanother.ThislocationregistrationisrequiredeventhoughtheMNdoesnotcommunicatewithotherswhilemoving.ThesignalingcostassociatedwithlocationupdatesmaybecomeverysignificantasthenumberofMNsincreases.Moreover,ifthedistancebetweenthevisitednetworkandthehomenetworkislarge,thesignalingdelayislong.MobileIPisnotasatisfactor7Limitation3SecurityandQoS

Security–authenticationwithFAproblematic,fortheFAtypicallybelongstoanotherorganization–noprotocolforkeymanagementandkeydistributionhasbeenstandardizedintheInternet–patentandexportrestrictionsFirewalls–typicallymobileIPcannotbeusedtogetherwithfirewalls,specialsetupsareneeded(suchasreversetunneling)Limitation3Security8SecurityandQoSQoS–manynewreservationsincaseofRSVP–tunnelingmakesithardtogiveaflowofpacketsaspecialtreatmentneededfortheQoSSecurity,firewalls,QoSetc.aretopicsofcurrentresearchanddiscussions!SecurityandQoSQoS9MIP扩展1LowLatencyHandoffsinMobileIPv4RFC48812MobileIPv4FastHandoversRFC49883MobileIPPaging

rfc3132rfc31544MobileIPv4RegionalRegistrationRFC48575MobileIPv4DynamicHomeAgent(HA)Assignmentrfc44336WiMAXForum/3GPP2ProxyMobileIPv4rfc5563

draft-leung-mip4-proxy-mode-107MobileIPv4TraversalAcrossNATandVPNGateways

RFC3519andRFC52658OverviewoftheGPRSlogicalarchitectureMIP扩展10OtherExtensionsSrisuresh,P.andM.Holdrege,"IPNetworkAddressTranslator(NAT)TerminologyandConsiderations",RFC2663,August1999.Srisuresh,P.andK.Egevang,"TraditionalIPNetworkAddressTranslator(TraditionalNAT)",RFC3022,January2001.rfc3519MobileIPTraversalofNetworkAddressTranslation(NAT)Devices2003Ferguson,P.andD.Senie,"NetworkIngressFiltering:DefeatingDenialofServiceAttackswhichemployIPSourceAddressSpoofing",BCP38,RFC2827,May2000.(Obsoletes:2267)Montenegro,G.,"ReverseTunnelingforMobileIP,revised",RFC3024,January2001.(Obsoletes:2344)rfc2356SunSKIPFirewallTraversalforMobileIP1998rfc4093ProblemStatementMobileIPv4TraversalofVirtualPrivateNetwork(VPN)Gatewaysdraft-ietf-mobileip-vpn-problem-solution-04MobileIPv4TraversalAcrossIPsec-basedVPNGateways2007.11OtherExtensionsSrisuresh,P.111.LowLatencyHandoffsinMobileIPv4

RFC48811.LowLatencyHandoffsinMobi12ch26-Limitation-of-Basic-Mobile-IP-移动IP技术-教学课件13Figure1.EventsequencingduringlinkswitchandIPhandover.AlinklayerprehandovernotificationeventAlinklayerlinkdowneventAlinklayerlinkupeventAnIPlayermovementdetectedeventAnIPlayerroutingchangedeventFigure1.Eventsequencingdur14LEPN—Alinklayerprehandovernotificationeventnotifyingoneoftheparticipantsinthehandoverthatahandoverispending.•LELD—AlinklayerlinkdowneventnotifyingoneoftheparticipantsinthehandoverthattheMobileNode’slinktotheoldAccessPointhasbeensevered.•LELU—AlinklayerlinkupeventnotifyingoneoftheparticipantsinthehandoverthattheMobileNode’slinktothenewAccessPointissufficientlyestablishedforIP(network)layertraffic.•NEMD—AnIPlayermovementdetectedeventnotifyingoneoftheparticipantsinthehandoverthattheMobileNodehaschangedIPsubnetsandthereforemustregisterwiththenewForeignAgentandre-registeranewcareofaddresswiththeHomeAgent.•NERC—AnIPlayerroutingchangedeventnotifyingoneoftheparticipantsinthehandoverthatregistrationwiththenewForeignAgentandHomeAgentiscomplete,andthatthereforetheMobileNode’sroutinghasbeenchangedtothenewsubnet.LEPN—Alinklayerprehandover154.4.3LowLatencyHandoffsinMobileIPv4rfc4881receivesanAgentAdvertisementperiodicallyfromaForeignAgentofthenewsubnet.mobiledevicecanonlyinitiatesthenetwork-layerhandover.MIPv4hasbeendesignedwithoutassuminganyinteractionbetweenlinkandnetworklayers.4.4.3LowLatencyHandoffsin16Twoobjectivesof

LowLatencyHandoffs1Interactionbetweenlinkandnetworklayersisachievedvialink-layertriggersviaeventnotificationsfromthelinklayertothenetworklayer.Link-layertriggersservetoinitiatethenetwork-layerhandoverbeforethelink-layerhandover2Establishingabi-directionaltunnelbetweenpreviousandnewFA

outageperiodisreducedTwoobjectivesof

LowLatency17Pre-RegistrationHandoverMethodupdateofthedatapathattheHomeAgentbeforetheactuallink-layerhandovermaybemobile-initiatedornetwork-initiated.Pre-RegistrationHando18mobile-initiatedLink-layertriggeratmobiledevicenetwork-initiatedlink-layertriggeroccursatthecurrentFAnetwork-initiatedlink-layertriggeroccursatthenewFAregisterswithitsHAL2triggercontainanidentifierofthenewpointofattachment,thenewsubnetorthenewFA.currentFArequestsAgentAdvertisementofthenewFAbysendingaPrRtSoltothenewFA.RouterSolicitationforProxyAdvertisement(RtSolPr)ProxyRouterAdvertisement(PrRtAdv)mobile-initiatednetwork-initia19Post-RegistrationHandoverMethodBidirectionalEdgeTunnel(BET)Thenamepost-registrationhandovermethodispuzzlingbecausethismethodistriggeredbeforeconnectivitytothecurrentFAislost.WhenthecurrentFAreceivesalink-downtrigger,itstartstunnellingpacketstothepreviouslyestablishedBETPost-RegistrationHand20Post-registrationprocess:two-andthree-partyL2-MT-AnL2triggerthatoccursattheMN,informingofmovementtoacertainnFA(MobileTrigger).L2-STorsourcetrigger-AnL2triggerthatoccursatoFA,informingtheoFAthatL2handoffisabouttooccur.L2-TTortargettrigger-AnL2triggerthatoccursatnFA,informingthenFAthatanMNisabouttobehandedofftonFA.L2-LU-AnL2triggerthatoccursattheMNornFA,informingthattheL2linkbetweenMNandnFAisestablished.L2-LD-AnL2triggerthatoccursattheoFA,informingtheoFAthattheL2linkbetweenMNandoFAislost.HRqstHandoffRequestHRplyHandoffReplyHTTHandofftoThird

Post-registrationprocess:two212MobileIPv4FastHandovers

RFC

49882MobileIPv4FastHandovers

R22Overviewadaptsthefasthandoverspecification[rfc4068]toIPv4networks.Koodli,R.,Ed.,"FastHandoversforMobileIPv6",RFC4068,July2005.TheprotocolavoidsthedelayduetomovementdetectionandIPconfigurationanddisengagesMobileIPregistrationdelayfromthetime-criticalpath.使脱离,使松开Overviewadaptsthefasthandov23TerminologyMobileNode(MN):AMobileIPv4host.AccessPoint(AP):ALayer2deviceconnectedtoanIPsubnetthatofferswirelessconnectivitytoanMN.AnAccessPointIdentifier(AP-ID)referstotheAP'sL2address.Sometimes,AP-IDisalsoreferredtoasaBaseStationSubsystemID(BSSID).AccessRouter(AR):TheMN'sdefaultrouter.

PreviousAccessRouter(PAR):TheMN'sdefaultrouterpriortoitshandover.NewAccessRouter(NAR):TheMN'sdefaultroutersubsequenttoitshandover.PreviousCoA(PCoA):TheIPaddressoftheMNvalidonPAR'ssubnet.NewCoA(NCoA):TheMN'sCare-ofAddressvalidonNAR'ssubnet.Handover:AprocessofterminatingexistingconnectivityandobtainingnewIPconnectivity.(AP-ID,AR-Info)tuple:Containsanaccessrouter'sL2andIPaddresses,andtheprefixvalidontheinterfacetowhichtheAccessPoint(identifiedbyAP-ID)isattached.Thetriplet[Router'sL2address,Router'sIPaddress,Prefix]iscalled"AR-Info".TerminologyMobileNode(MN):A24Figure1:PredictiveFastHandoverMNPARNAR||||------RtSolPr------->|||<-----PrRtAdv--------||||||------FBU----------->|--------HI--------->|||<------HAck---------||<--FBack---|--FBack--->||||disconnectforward||packets===============>|||||||connect||||||---------FBU--------------------------->||<===================================deliverpackets||(includingFBack)Figure1:PredictiveFastHandoverRouterSolicitationforProxyAdvertisement(RtSolPr)ProxyRouterAdvertisement(PrRtAdv)HandoverInitiate(HI)HandoverAcknowledge(HAck)Figure1:PredictiveFastHand25Figure2:ReactiveFastHandoverMNPARNAR||||------RtSolPr------->|||<-----PrRtAdv--------|||||disconnect||||||||connect|||-----------FBU-------|------------------->|||<-----FBU-----------|||------FBack-------->||forward||packets===============>|||||<===================================deliverpackets|(includingFBack)||Figure2:ReactiveFastHandoverFastBindingUpdate(FBU)FastBindingAcknowledgment(FBAck)Figure2:ReactiveFastHandov263MobileIPPagingX.Zhang,G.Castellanos,andA.T.Campbell,“P-MIP:PagingextensionsforMobileIP,”MobileNetworksandApplications(MONET),vol.7,no.2,pp.127–141,March2002.J.KempfandP.Mutaf,IPpagingconsideredunnecessary:MobileIPv6andIPpagingfordormantmodelocationupdateinmacrocellularandhotspotnetworks,InIEEEWirelessCommunicationsandNetworkingConference,NewOrleans,Louisiana,USA,March2003.rfc3132DormantModeHostAlerting(IPPaging)ProblemStatementrfc3154RequirementsandFunctionalArchitectureforanIPHostAlertingProtocol3MobileIPPagingX.Zhang,G.27MobileIPPaging[9]H.HaverinenandJ.Malinen,“MobileIPRegionalPaging,”Internetdraft,IETF,draft-haverinen-mobileip-reg-paging-00.txt,June2000,workinprogress.InordertosavebatterypowerconsumptionatMNs,IPpagingisproposedasanextensionforMobileIP[9].UnderMobileIPpaging,anMNisallowedtoenterapowersavingidlemodewhenitisinactiveforaperiodoftime.Duringidlemode,thesystemknowsthelocationoftheMNwithcoarseaccuracydefinedbyapagingareacomposedofseveralsubnets[9].MobileIPPaging[9]H.Haverin28MobileIPPagingTheMNmayalsodeactivatesomeofitscomponentsforenergy-savingpurposes.AnMNinidlemodedoesnotneedtoregisteritslocationwhenmovingwithinapagingarea.Itperformslocationupdateonlywhenitchangespagingareas.WhenpacketsaredestinedtoanMNinidlemode,theyareterminatedatapaginginitiator.ThepaginginitiatorbuffersthepacketsandlocatestheMNbysendingoutIPpagingmessageswithinthepagingarea.AfterknowingthesubnetwheretheMNresides,thepaginginitiatorforwardsthedatapacketstotheservingFAofthesubnetandfurthertotheMN.WhenanMNisinactivemode,itoperatesinthesamemannerasinMobileIP,andthesystemkeepstheexactupdatedlocationinformationoftheMN.MobileIPPagingTheMNmayals29ch26-Limitation-of-Basic-Mobile-IP-移动IP技术-教学课件30PagingprotocolsPagingprotocols314MobileIPv4RegionalRegistration

RFC48574MobileIPv4RegionalRegistr32MacroandMicro-MobilityMacro-Mobility–Largergeographicarea.FewerhandoffsMicro-Mobility–Smallgeographicarea.FrequentandfasthandoffsMacroandMicro-MobilityMacro-33MacroandMicromobilityHomeNetwork

INTERNETHomeAgentFAMicro-mobilityhandoverMacro-mobilityhandoverMacromobilitybyMobileIP

MicromobilitydomainGatewayasFAHandoversinMicroMobilitytransparentoutsidethedomainMacroandMicromobilityHomeN34MobileIParchitecture.MobileIProducealayerofhierarchyinthevisiteddomain.anewnetworkentitycalledaGatewayForeignAgent(GFA)Regionalregistrationsreducethenumberofsignalingmessagestothehomenetwork,andreducethesignalingdelaywhenamobilenodemovesfromoneforeignagenttoanotherwithinthesamevisiteddomain.regionalregistrationsregistra36TerminologyForeignAgent(FA)Asdefinedin[RFC3344].GatewayForeignAgent(GFA):AForeignAgentwhichhasapubliclyroutableIPaddress.AGFAmay,forinstance,beplacedinornearafirewall.Visiteddomain:Thedomainwherethevisitednetwork,thecurrentforeignagent,andtheGFAarelocated.TerminologyForeignAgent(FA)37GeneralAssumptions+---------------------------++----------------+|VisitedDomain||Home|||+---------+|Network||||||||+------++-------+||Public||+------+|||FA|------|GFA|-------------------------|HA|||+--+---++-------+||Network||+------+||||||||+-----|---------------------++---------++----------------+|+--+---+|MN|+------+Figure1:ModelofOperationGeneralAssumptions38ProtocolOverview

MNFA1GFAHA|||||RegistrationRequest||||---------------------->|Reg.Request||||---------------------->|Reg.Request||||--------------->||||Reg.Reply|||Reg.Reply|<---------------||RegistrationReply|<----------------------|||<----------------------|||||||Figure2:HomeRegistrationMNFA2GFAHA|||||RegionalReg.Req.||||---------------------->|RegionalRegistrationReq.||||----------------------------->||||RegionalRegistrationReply|||RegionalReg.Reply|<-----------------------------|||<----------------------|||||||Figure3:RegionalRegistrationProtocolOverviewMN39HomeregistrationHomeregistrationisperformedwhenaMNfirstarrivesatavisiteddomain,whenitrequestsanewHA,orwhenitchangesGFA.Thecare-ofaddressthatisregisteredattheHAistheaddressofaGFA.

TheGFAkeepsavisitorlistofalltheMNscurrentlyregisteredwithit.Sincethecare-ofaddressregisteredattheHAistheGFAaddress,itwillnotchangewhentheMNchangesFAunderthesameGFA.Thus,theHAdoesnotneedtobeinformedoffurtherMNmovementswithinthevisiteddomain.HomeregistrationHomeregistra40RegionalRegistrationAmobilenodeperformsregistrationlocallyatthevisiteddomain,bysendingaRegionalRegistrationRequesttoaGFA,andreceivingaRegionalRegistrationReplyinreturn.LocalCare-ofAddress:Acare-ofaddressthatisassignedtoeitheramobilenodeoraforeignagentofferinglocalconnectivitytoamobilenode.AregistrationmessagefromthemobilenodeissubsequentlysenttoaGFAviathelocalcare-ofaddressMNFA2GFAHA|||||RegionalReg.Req.||||---------------------->|RegionalRegistrationReq.||||----------------------------->||||RegionalRegistrationReply|||RegionalReg.Reply|<-----------------------------|||<----------------------|||||||Figure3:RegionalRegistrationRegionalRegistrationAmobile411.MN移动到FA的覆盖范围时的注册过程代理广播注册请求注册回复1.MN移动到FA的覆盖范围时的注册过程代理广播注册请求注册422.注册完成后隧道的建立注册完成后建立两条隧道：HA——HFA、HFA——FA，两条隧道通过HA、HFA和FA上四个虚拟接口连接完成

2.注册完成后隧道的建立注册完成后建立两条隧道：HA——HF433.MN与HA通信时数据包走过的路径MNHAMN发送的数据包eth1（FA）TUNL0（FA）TUNL0（HFA）TUNL1（HFA）TUNL0（HA）eth0（HA）HAMNHA发送的数据包TUNL0（HA）TUNL1（HFA）TUNL0（HFA）TUNL0（FA）eth1（FA）MN3.MN与HA通信时数据包走过的路径MNHAMN发送的et44DynamicGFAAssignmentThevisitednetwork(i.e.,theFA)indicatessupportfordynamicGFAassignmentTheMNrequestsadynamicallyassignedGFAUponreceivingthisRegistrationRequest,theFArelaysittotheappropriateGFA,andtheGFAassignsitsaddresstotheMNbymeansofaGFAIPAddressextensionaddedtotheRegistrationRequestDynamicGFAAssignmentThevisi455DynamicHomeAgentDiscoveryinMobileIPv4–RFC4433MobileIPv4[1]specifiesthemechanismfordiscoveringthemobilenode'shomeagentusingsubnet-directedbroadcastIPaddressinthehomeagentfieldoftheRegistrationRequest.Thismechanismwasdesignedformobilenodeswithastatichomeaddressandsubnetprefix,anchoredonfixedhomenetwork.

However,usingsubnet-directedbroadcastasthedestinationIPaddressoftheRegistrationRequest,itisunlikelythattheRegistrationRequestwillreachthehomesubnetbecauserouterswilldropthesepacketsbydefault.SeeCERTAdvisoryCA-1998-01SmurfIPDenial-of-ServiceAttacks[3].[1]Perkins,C.,"IPMobilitySupportforIPv4",RFC3344,August2002.[3]Senie,D.,"ChangingtheDefaultforDirectedBroadcastsinRouters",BCP34,RFC2644,August1999.5DynamicHomeAgentDiscovery46MobileIPv4DynamicHomeAgent(HA)AssignmentTheMobileIPv4NAIExtensionforIPv4[2]introducedtheconceptofidentifyinganMNbytheNAIandenablingdynamichomeaddressassignment.

[2]Calhoun,P.andC.Perkins,"MobileIPNetworkAccessIdentifierExtensionforIPv4",RFC2794,March2000.Whenthehomeaddressisdynamicallyassigned,itisdesirabletodiscoverthehomeagentdynamicallyorinformtheMNaboutanoptimalHAtouseforamultitudeofreasons,suchas:Ifthedistancebetweenthevisitednetworkandthehomenetworkofthemobilenodeislarge,thesignalingdelayfortheseregistrationsmaybelong.Insuchacase,theMNwillbeanchoredtoitsdistanthomeagent,resultingintunneledtraffictravelingalongdistancebetweenhomeagentandthemobilenode.WhenaMobileIPsessioninitiates,ifthemobilenodecanbeassignedahomeagentthatisclosetothemobilenodeitcandrasticallyreducethelatencybetweenthehomeagentandmobilenode.Inalarge-scaleMobileIPdeployment,itiscumbersometoprovisionMNswithmultipleHAaddresses.ItisdesirabletoachievesomeformofloadbalancingbetweenmultipleHAsinthenetwork.DynamicHAassignmentand/orHAredirectionletsthenetworkselecttheoptimalHAfromamongasetofHAsandthusachieveloadbalancingamongagroupofHAs.Localadministrativepolicies.MobileIPv4DynamicHomeAgent47ThemechanismbywhichthenetworkselectsanHATheselectionmaybemadebyanynetworknodethatreceivestheRegistrationRequest(orinformationabouttheRegistrationRequest),suchasaForeignAgent,AAAserver,orhomeagent.ThenodethatselectstheHAmayselectonebasedonanumberofcriteria,includingbutnotlimitedtoHAload-balancing,geographicalproximity,administrativepolicy,etc.Themechanismbywhichthenet48ch26-Limitation-of-Basic-Mobile-IP-移动IP技术-教学课件496WiMAXForum/3GPP2ProxyMobileIPv4

draft-leung-mip4-proxy-mode-04

rfc55636WiMAXForum/3GPP2ProxyMobi50WiMAXForum/3GPP2ProxyMobileIPv4therearemanyIPv4deviceswithoutMobileIPv4capabilityduetovariousreasons.OperationsystemslacksupportMobilitystillneededforthesedevicesThesearesomeexamplesofProxyMobileIPv4:1.AWLANaccesspointorcellularbasestationperformsregistrationwiththeHomeAgentwhenamobiledeviceisassociatedontheair-link.2.AnaccessrouterorForeignAgentperformsregistrationwiththeHomeAgentwhenamobiledeviceisdetectedonthenetwork.WiMAXForum/3GPP2ProxyMobile51ProxyMobileIPv4MobilestationIPv4hostwithoutMobileIPfunctionProxyMobileIPv4Client(PMIPClient)ThisnetworkfunctionisresponsibleforinitiatingandmaintainingtheproxyMobileIPv4registrationonbehalfofthemobiledevice.ProxyMobilityAgent(PMA)PMAisthelogicalentityinthenetworkthatencompassesboththePMIPClientandtheFAfunctions.ThePMIPClientandtheFAcollocationintheAccessRouterconstituteanintegratedPMA.WhenthePMIPClientandtheFAfunctionsarenotcollocatedintheAccessRouter,itisreferredasasplitPMA.ProxyMobileIPv4Mobilestatio52BenefitsSupportforUnmodifiedHostsRe-useofExistingHomeAgentReductionofAir-linkResourceConsumptionSupportforHeterogeneousWirelessLinkTechnologiesSupportforIPv4andIPv6HostBenefitsSupportforUnmodified53ProxyRegistrationduringInitialNetworkAttachment

+----++-------++-------++-----+|||AR/||||||MN||PMA||AAA||HA|||||||||+----++-------++-------++-----+|||||1a|1b||Authentication|<------------->|<----------->|||||||2|||+->|-------------->||||||3|||||-------------------------->|<-+Address||||PMIP|Acquisition|||4||||||<--------------------------|<-+||5|||+->|<--------------|||||||