垂直切换的策略研究

第10卷第2期信息工程大学学报Vol10No22009年6月JournalofInformationEngineeringUniversityJun2009:2008-09-05:(60870015,60674008);973(2007CB307100,2007CB307101):(1985-),,,,;(1965-),,,,延志伟,周华春,张宏科,张思东(,100044):下一代无线网络中,异构切换技术是融合多个异构接入网络的关键技术之一近年来,随着无线通信技术的蓬勃发展,如何使用多个异构网络接口达到无缝的异构切换成为研究热点多个接口可以采用不同的触发机制和使用规则,这将需要不同的协议实现支持并带来不同的实际切换性能文章对异构切换中的多接口使用机制以及触发规则进行详细研究,并对不同的多接口使用机制和异构切换触发机制的4种不同组合进行仿真比较从仿真结果可以看到,切换过程中采用链路层的信息能够及时触发即将发生的切换,另外,如果采用多个接口预先建立连接的机制,能够最大限度的减少切换延时因此,这两种机制的组合能够带来最佳的切换效果:异构切换;策略;垂直切换;多家乡:TP393:A:1671-0673(2009)02-0280-05StudyoftheVerticalHandoverPoliciesYANZh-iwe,iZHOUHua-chun,ZHANGHong-ke,ZHANGS-idong(SchoolofElectronicsandInformationEngineering,BeijingJiaotongUniversity,Beijing100044,China)Abstract:InNex-tGeneration(NG)wirelessnetworks,verticalhandovertechniquesareexpectedtoenabletheintegrationofheterogeneousnetworks.Howtomakeuseofmultipleheterogeneousinter-facestofacilitatetheseamlessverticalhandoverisahottopicinrecentyeaswiththedevelopmentofwirelesscommunication.Multipleinterfacescancomeinavarietyofwaystouseinaccordancewithdifferenttriggeringschemeintheverticalhandover,andmayresultindifferentrequirementsonpro-tocolsandperformance.Inthispaper,theauthorsstudymult-iinterfaceschemesandtriggeringschemesforhandoverinheterogeneouswirelessnetworks.AndwesimulatetheseschemesinNS2tocomparethehandoverperformance.Fromthesimulationresults,wecanseethelinklayerinforma-tioncanbewellusedtotriggertheoncominghandoverintime,ontheotherhand,pre-establishedmultiplepathscanbeusedtodecreasethehandoverlatency.Sothesetwoschemescombinedusingcanproducethebestperformanceofverticalhandover.Keywords:verticalhandover;policies;verticalhendwer;multihoming,IP,,[1,2]2:281,,:,;,,1,,,1,2[3~5],,IEEE2006802.21[6],L2,L2L3MediaIn-dependentHandover(MIH),L2,MIHfunction,L2(L2trigger),,:,[7],[8],MIP,,,[7,9,11,12],,,MobileIPv4SimultaneousMobilityBinding(SB-MIP)[13]IETF組MobileNodesandMultipleInter-facesinIPv6(Monami6),MobileIPv6[14],Care-ofaddress(CoA)2,,2,,,:,:,,,;,,41,,1情景1(没有链路层辅助+新连接触发建立),,,,,,2822009,,情景2(没有链路层辅助+新连接预先建立),,,,,,情景3(链路层辅助+新连接触发建立),,,,,,,,,情景4(链路层辅助+新连接预先建立),,,,,34,NS2WMiAXWLAN,WLANBS-BASEStationAP-AccessPointCN-CorrespondingNodeMN-MobileNode2WMiAXWLAN(CN)WMiAX,WLAN,,WMiAXNISTNS2.29,MIH33WLAN,MIHWLANRSS,RSS,,,shu-tdown,shutdown=1,WLAN,(WMiAX)down,WMiAX,,,,WMiAXshutdown=0,WLAN,WMiAXup,WMiAX,WMiAXWMiAX,shutdown=1,WLANdown,,WMiAX,2:283WLANWLAN,RSS-47dbmRSS-200dbmWLAN,,CN100Mbps,30msWMiAXBSWLANAP100Mbps,15msMNCN5sUDP,CBR,160byte,50s444.11414,,WLANRSS,,,WLAN,,,WMiAX,,,,,,3.8,13324.225,52,WLANRSS,,,WLAN,,WMiAX,,,,,,0.4,1284.33636,,WLANRSS,,,,WLAN,,WLAN,WMiAX,,,,2842009,,0.2,814.447,,WLANRSS,,WMiAX,,,,,0.1,3574,,,,,,,,,,,,,,,,,,,,,,5,,,,,,NS2,,:[1]AndrF,BonninMJ,DeniauB,eta.lOptimizedSup-portofMultipleWirelessInterfaceswithinanIPv6End-terminal[C/OL]//presentedatSmartObjectsConference(SOC2'003),Grenoble,France(2003-05-1).[2]NgWC,ErnstT.Multipleaccessinterfacesformobilenodesandnetworks[C]//IEEEInternationalConferenceonNetworksICON.November2004:774-779.[3]AbobaB,Ed.ArchitecturalImplicationsofLinkIndica-tions[Z].InternetDraft,draft-iab-linkindications-04txt,IETF,2005.[4]KempfJ.SupportingOptimizedHandoverforIPMobility-RequirementsforUnderlyingSystems[Z].InternetDraft,draft-manyfolks-l2-mobilereq-02.txt,IETF,2002.[5]YeginA.Link-layerHintsforDetectingNetworkAttach-ments[Z].InternetDraft,draft-yegin-dnal2-hints-01.txt,IETF,2004.[6]IEEE802.21/D01.00.DraftIEEEStandardforLocalandMetropolitanAreaNetworks:MediaIndependentHan-doverServices[S].2006.[7]MontavontN.AnalysisofMultihominginMobileIPv6[Z].InternetDraft,draft-iet-fnemo-multihomingissues-07.txt,IETF,2007.[8]YlitaloJ.Dynamicnetworkinterfaceselectioninmult-ihomedmobilehosts[C]//presentedatThe36thAnnualHawaiiInternationalConferenceonSystemSciences.2003:7-10.(下转第288页)2882009[10],CNM,115000.4110000.4420000.45,,,3,,,,:[1],,,.[J].,2006,29(1):1-8.[2].[R].:,2007.[3]DoarMB.Abettermodelforgeneratingtestnetworks[C]//Proc.oftheGLOBECOM96.1996:86-93.[4]ZeguraEW,CalvertKL,DonahooMJ.Aquantitativecom-parisonofgraphbasedmodelsforInternettopology[J].IEEE/ACMTrans.onNetworking,l997,5(6):770-783.[5]PalmerCR,SteffanJG,Generatingnetworktopologiesthatobeypowerlaws[C]//Proc.oftheGLOBECOM2000.2000:434-438.[6]AielloW,ChungF,LuLY.Arandomgraphmodelformassivegraphs[C]//Proc.oftheACMSTOC2000.2000:171-180.[7]BarabasiAL,AlbertR.Emergenceofscalinginrandomnetworks[J].Science,1999,286(5439):509-512[8]AlbertR,BarabasiAL.Topologyofevolvingnetworks:lo-caleventsanduniversality[J].PhysicalReviewLetters,2000,85(24):5234.[9],.AS[J].,2006,3(3):34-41.[10],,,.Internet[J],2007,4(3):17-28.(上接第284页)[9]ErnstT,Ed.GoalsandBenefitsofMultihoming[Z].In-ternetDraft,draft-ernst-generic-goalsand-benefits-01.txt,IETF,2005.[10]NgCW,ErnstT.MultipleAccessInterfacesforMobileNodesandNetworks[C]//Proceedingsof12thIEEEIn-ternationalConferenceonnetworks(ICON2004).2004:774-779.[11]MontavontN,Ed.MobileIPv6formultipleinterfaces(MMI)[Z].InternetDraft,draft-montavont-mip6-mm-i02.txt,IETF,2005.[12]TheI