rfc3561-Ad-hoc-On-Demand-Distance-Vector-(AODV)

NetworkWorkingGroupC.PerkinsRequestforComments:3561NokiaResearchCenterCategory:ExperimentalE.Belding-RoyerUniversityofCalifornia,SantaBarbaraS.DasUniversityofCincinnatiJuly2003AdhocOn-DemandDistanceVector(AODV)RoutingStatusofthisMemoThismemodefinesanExperimentalProtocolfortheInternetcommunity.ItdoesnotspecifyanInternetstandardofanykind.Discussionandsuggestionsforimprovementarerequested.Distributionofthismemoisunlimited.CopyrightNoticeCopyright(C)TheInternetSociety(2003).AllRightsReserved.AbstractTheAdhocOn-DemandDistanceVector(AODV)routingprotocolisintendedforusebymobilenodesinanadhocnetwork.Itoffersquickadaptationtodynamiclinkconditions,lowprocessingandmemoryoverhead,lownetworkutilization,anddeterminesunicastroutestodestinationswithintheadhocnetwork.Itusesdestinationsequencenumberstoensureloopfreedomatalltimes(eveninthefaceofanomalousdeliveryofroutingcontrolmessages),avoidingproblems(suchascountingtoinfinity)associatedwithclassicaldistancevectorprotocols.TableofContents1.Introduction...............................................22.Overview..................................................33.AODVTerminology...........................................44.ApplicabilityStatement....................................65.MessageFormats............................................75.1.RouteRequest(RREQ)MessageFormat...................75.2.RouteReply(RREP)MessageFormat.....................85.3.RouteError(RERR)MessageFormat.....................105.4.RouteReplyAcknowledgment(RREP-ACK)MessageFormat..116.AODVOperation.............................................116.1.MaintainingSequenceNumbers..........................116.2.RouteTableEntriesandPrecursorLists...............13Perkins,et.al.Experimental[Page1]RFC3561AODVRoutingJuly20036.3.GeneratingRouteRequests.............................146.4.ControllingDisseminationofRouteRequestMessages...156.5.ProcessingandForwardingRouteRequests..............166.6.GeneratingRouteReplies..............................186.6.1.RouteReplyGenerationbytheDestination......186.6.2.RouteReplyGenerationbyanIntermediateNode...........................................196.6.3.GeneratingGratuitousRREPs....................196.7.ReceivingandForwardingRouteReplies................206.8.OperationoverUnidirectionalLinks...................216.9.HelloMessages........................................226.10MaintainingLocalConnectivity........................236.11RouteError(RERR)Messages,RouteExpiryandRouteDeletion..............................................246.12LocalRepair..........................................266.13ActionsAfterReboot.................................276.14Interfaces............................................287.AODVandAggregatedNetworks...............................288.UsingAODVwithOtherNetworks.............................299.Extensions.................................................309.1.HelloIntervalExtensionFormat.......................3010.ConfigurationParameters...................................3111.SecurityConsiderations....................................3312.IANAConsiderations........................................3413.IPv6Considerations........................................3414.Acknowledgments............................................3415.NormativeReferences.......................................3516.InformativeReferences.....................................3517.Authors’Addresses.........................................3618.FullCopyrightStatement...................................371.IntroductionTheAdhocOn-DemandDistanceVector(AODV)algorithmenablesdynamic,self-starting,multihoproutingbetweenparticipatingmobilenodeswishingtoestablishandmaintainanadhocnetwork.AODVallowsmobilenodestoobtainroutesquicklyfornewdestinations,anddoesnotrequirenodestomaintainroutestodestinationsthatarenotinactivecommunication.AODVallowsmobilenodestorespondtolinkbreakagesandchangesinnetworktopologyinatimelymanner.TheoperationofAODVisloop-free,andbyavoidingtheBellman-Fordcountingtoinfinityproblemoffersquickconvergencewhentheadhocnetworktopologychanges(typically,whenanodemovesinthenetwork).Whenlinksbreak,AODVcausestheaffectedsetofnodestobenotifiedsothattheyareabletoinvalidatetheroutesusingthelostlink.Perkins,et.al.Experimental[Page2]RFC3561AODVRoutingJuly2003OnedistinguishingfeatureofAODVisitsuseofadestinationsequencenumberforeachrouteentry.Thedestinationsequencenumberiscreatedbythedestinationtobeincludedalongwithanyrouteinformationitsendstorequestingnodes.Usingdestinationsequencenumbersensuresloopfreedomandissimpletoprogram.Giventhechoicebetweentworoutestoadestination,arequestingnodeisrequiredtoselecttheonewiththegreatestsequencenumber.2.OverviewRouteRequests(RREQs),RouteReplies(RREPs),andRouteErrors(RERRs)arethemessagetypesdefinedbyAODV.ThesemessagetypesarereceivedviaUDP,andnormalIPheaderprocessingapplies.So,forinstance,therequestingnodeisexpectedtouseitsIPaddressastheOriginatorIPaddressforthemessages.Forbroadcastmessages,theIPlimitedbroadcastaddress(255.255.255.255)isused.Thismeansthatsuchmessage