Impact of resource reservation on the distributed

ImpatofResoureReservationonDistributedMulti{pathQualityofServieRoutingShemesYuanZhongXinYuanDepartmentofComputerSieneFloridaStateUniversityTallahassee,FL32306fzhong,xyuangs.fsu.eduAbstratThispaperonsiderstheimpatofresourereservationonthemulti{pathQuality{of{Servie(QoS)routingshemesthatuseglobalnetworkstatetomakeroutingdeisions.Inorporatingresourereservationintomulti{pathQoSroutingalgorithmsangreatlyhangetheommuniationharateristisinanetworksystemandaettheperformaneoftheroutingalgorithms.Inthispaper,wedevelopanewQoSroutingprotoolthatombinesresourereservationwiththetiket{baseddistributedmulti{pathQoSroutingsheme,evaluatethenewroutingprotoolthroughextensivesimulation,studytheimpatsofothernetworkomponents,suhasthelinkstateupdatemehanisms,ontheperformaneofmulti-pathQoSroutingshemeswithresourereservation,andomparemulti-pathroutingshemeswithotherroutingprotoolsinludingsingle{pathroutingshemesandoodingbasedroutingshemes.1IntrodutionThemigrationtointegratednetworksforvoie,dataandmultimediaappliationintroduesnewhallengesinsupportingpreditableommuniationperformane.Multimediaapplia-tionsrequiretheommuniationtomeetstringentrequirementondelay,delay{jitter,ostand/orotherqualityofservie(QoS)metris.Tosupportsuhappliations,thenetworkmustbeabletoprovideommuniationhannelswithQoSguarantees.Twokeyissues,QoSrouting,whihidentiespathsthatmeettheQoSrequirementandseletstheonethatleadstohighoverallresoureeÆieny,andresourereservation,whihreservestheresouresinthepath,mustbeaddressedtosupportommuniationswithQoSguarantees.AlthoughQoSroutingandresourereservation[15℄aretwoloselyrelatednetworkompo-nents,traditionally,thesetwotasksareseparatedintotwosteps.First,arouteisseleted,thentherouteisset{upandtheresouresarereservedalongtheroute.Separatingroutingandresourereservationsimpliestheprotooldesign.However,inB{ISDN,resoureavailabilitymayhangerapidlyandtherouteinformationmaybeoutdated.Insuhenvironment,aroutethatwasomputedintherststepmaylaktheresouresintheseondstep.Combiningthetwostepswassuggestedtooveromethisproblem[5,8℄.CombiningresourereservationandQoSroutingangreatlyhangetheommuniationharateristisinthenetworksystemandaettheperformaneoftheroutingalgorithms.ManyQoSroutingalgorithmshavebeendesignedtodeterminetheroutetoestablishaonnetion[2,5,6,7,9,10,12,13,14℄.Amongthesealgorithms,multi{pathQoSroutingshemes[3℄thatuseglobalnetworkinformationtomakeroutingdeisionsarepromisingforfuturenetworksforthefollowingreasons.First,byusingtheglobalnetworkinformation,theseprotoolswillinurlessmessagingoverheadomparedtotheoodingbasedprotoolsthatdonotusetheglobalnetworkinformationtomakeroutingdeisions.Seond,byexploringmultiplepathssimultaneouslyinsearhofthepaththatsatisestheQoSrequirementofaonnetion,multi{pathQoSroutingalgorithmsaremoreeetive,intermsofboththeblokingprobabilityandthepathestablishmenttime,thansingle{pathQoSroutingshemesthatexploreonepathatatime.Resourereservationmay,however,aettheperformaneofthemulti{pathQoSroutingalgorithmsthatuseglobalnetworkstateinformationmorethanitaetstheperformaneofthesingle{pathQoSroutingalgorithmsortheoodingbasedalgorithms.Inmulti{pathrouting,multiplepathsareprobedsimultaneously,whihmayrequirereservingresouresonmultiplepathsforeahonnetionrequest.Thisproblemisalledtheoverreservationproblem.Furthermore,reservingresouresonmultiplepathsangreatlyhangetheresoureavailabil-ityharateristisinthenetworksystemanddereasethepreisionoftheglobalnetworkstateinformation.Sinethealgorithmsrelyontheglobalnetworkstatetomakeeetiveroutingdeisions,theimpatofresourereservationonthepreisionoftheglobalnetworkstateinformationangreatlyaettheperformaneofthealgorithms.Thus,inorporatingresourereservationinmulti{pathQoSroutingalgorithmsnotonlyrequiresthedesignofneweÆientprotoolsthatombineresourereservationandQoSrouting,butalsorequiresthere{evaluationoftheperformaneissuesintheroutingalgorithms.Inthispaper,wedevelopanewQoSroutingprotoolthatombinesresourereservationandavariationofthetiket{basedQoSroutingsheme[3℄,whihisadistributedmulti{pathQoSroutingshemedesignedtodealwithimpreisestateinformation.Weevaluatetheperformaneofnewprotoolsthroughextensivesimulation.Oneuniquefeatureofthetiket{basedQoSroutingshemeisthatthenumberofpathstobeprobedinparallelisontrolledbythenumberoftiketsgeneratedforeahonnetionrequest.Bymanipulatingthenumberoftiketsforeahrequest,thetiket{basedroutingshemeanemulateawiderangeofQoSroutingshemesinludingoodingbasedQoSroutingshemesandsingle{pathQoSroutingshemes.Thus,introduingresourereservationintothetiket{basedQoSroutingenablesustostudytheimpatofresourereservationonawiderangeofQoSroutingalgorithms.Ourresultsshowthatmulti{pathQoSroutingshemes(withresourereservation)aremoreeetiveinndingpathsthatsatisfytheQoSrequirementofaonnetionthansingle{pathQoSroutingshemeswhenthenetworkisunderlighttraÆload.WhenthenetworkisunderheavytraÆ,multi{pathroutingisbetterthanthesingle{pathroutingwhentheresourerequirementofeahonnetionislowandthenetworkisnotsaturated.Single{pathQoSroutingshemesaremoreeÆientwhenthenetworkisunderheavyloadandtheresourerequire