计算机学报

	Chinese Journal of Computers Full Text
Title	NetworkFunctionVirtualizationTechnology:ASurvey
Authors	WANGJin-Wen1)ZHANGXiao-Li2),3),4)LIQi2),3)WUJian-Ping1),2),4)JIANGYong1),3)
Address	1)(Tsinghua-BerkeleyShenzhenInstitute,TsinghuaUniversity,Shenzhen,Guangdong518055) 2)(InstituteforNetworkScienceandCyberspace,TsinghuaUniversity,Beijing100084) 3)(GraduateSchoolatShenzhen,TsinghuaUniversity,Shenzhen,Guangdong518055) 4)(DepartmentofComputerScienceandTechnology,TsinghuaUniversity,Beijing100084)
Year	2019
Issue	No.2(415-436)
Abstract & Background	AbstractVariousmiddleboxeshavebeendeployedtoenablediversifiedfunctionalitiesinenterprisenetworks.Forexample,FirewallsandIntrusionDetectionSystemsareusedtoenhancethesecurityofthenetwork,andCacheProxiesandWANOptimizationsareusedtoimprovetheperformanceoftheenterprisenetworks.However,itispainfulforenterprisestodeploy,update,ormaintainsuchphysicaldevicesintheirenterprisenetworks.Moreover,becauseofthediscrepancybetweennetworkfunctiondevicesofthedifferentmanufacturers,enterprisesneedtohirelargemanagementteamswithextensiveknowledgetomanagethenetworkfunctionsdevices.Becauseofthefixedlocationandnetworktrafficprocesscapacityofthehardwarenetworkfunctiondevices,thenetworktrafficcongestionalwayscausesthefailureofthenetworkfunctions.Theoverheadofmiddleboxmanagement,maintenanceandupdateincreasesignificantlyasenterprisenetworksgrow.Fortunately,theemergingNetworkFunctionVirtualization(NFV)technologycanaddresstheseissuesbydecouplingthephysicalnetworkequipmentfromthenetworkfunctionsthatrunonthem.WiththeNFVtechnology,anenterprisecanefficientlyreducecomplicatednetworkfunctionmanagementandthecostofdeployingnetworkfunctionequipmentbydeployingnetworkfunctionsincommercialservers.Itcanalsoenableflexibleservicedeploymentstrategiesfortheenterprises,e.g.,dynamicallyscalein/out.AlthoughNFVcanbringsignificantbenefitstoenterprises,therearestillmanychallengesindevelopingpracticalandefficientNFV.Inordertosolvesuchproblems,researchersinacademiaandindustryhavedevotedtothestudyoftheNFVtechnology.ThispaperpresentsthefirstsystematicstudyoftheliteratureoftheNFVtechnology.Firstly,wereviewthestandardarchitectureofNFVestablishedbytheEuropeanTelecomStandardsInstituteIndustrySpecificationGroupforNFV(ETSIISGNFV).WeclassifyandsummarizetheproblemsandchallengesinthedevelopingofNFVsystemsbasedonthestandardarchitectureofNFV.Thestudycanbeclassifiedintothefollowingthreecategories:NetworkFunctionVirtualization,NetworkFunctionVirtualizationInfrastructure(NFVI),andManagementAndNetworkOrchestration(MANO).Furthermore,SoftwareDefinedNetwork(SDN)isanewtypeofnetworkarchitecturewhicharedesignedtoachieveflexibleandintelligentnetworktrafficcontrolbydecouplingthecontrolplaneanddataplaneofnetworkdevices,NFVandSDNcancomplementeachotherinvariousaspects,westudytherelationshipbetweentheNFVandSDN.Secondly,wesystematicallystudybuildingblocksofNFV,i.e.,virtualnetworkfunction(VNF)construction,andtherunningenvironmentoptimizationinNFV,thedesignofNFVmanagementsystemanditsoptimization,policyenforcementandverification,resourceallocationandmigration,loadbalanceandstatemanagementtechnology,andNFVsecurity.Thirdly,theNFVtechnologyhasbeendeployedindifferentkindsofindustryfields,weshowthepracticaldeploymentissuesofNFVbydiscussingtheapplicationscenariocasesofNFV,e.g.incloudcomputing,mobilecommunication,andhomenetwork.Finally,wesummarizetheadvantagesandshortcomingsofNFVbycomparingtheNFVtechnologyandclassicalphysical networkfunctiondevicesandpresentthefutureresearchdirectionsoftheNFVtechnologyfromsixaspectsbasedonthestandardarchitectureofETSINFV. Keywordsnetworkfunctionvirtualizationtechnology;networkfunction;virtualization;cloudcomputing;networksecurity BackgroundEnterprisesimprovetheirnetworkperformanceandsecuritiesbydeployingdifferentkindsofmiddleboxes,suchasfirewall,IntrusionDetectionSystem(IDS),WANOptimization,etc.However,withtheincreaseofthesizeoftheenterprisenetwork,thecostofmiddleboxesdeploymentandmaintenanceincreasessignificantly.Toaddresstheseproblems,NetworkFunctionVirtualization(NFV)hasbeenproposedtodeploythesoftwarenetworkfunctionsonthestandardcommercialserverwithhighperformancetosavethehardwarecostandsimplifythenetworkfunctionmaintenance.Inrecentyears,NFVtechnologyhasattractedsignificantattentionfromacademicandindustrialcommunities.Inthispaper,weprovideacomprehensivesurveyofexistingstudiesofNFVtechnology. Inthispaper,wefirstintroducedthestandardNFVarchitectureproposedbyETSI.ThenweclassifytheexistingresearchresultsofNFVtechnology.AndwediscusstheresearchworksonNFVtechnologyfromfollowingaspects: buildingblocksofNFV,i.e.,virtualnetworkfunction(VNF)construction,andtherunningenvironmentoptimizationinNFV,thedesignofNFVmanagementsystemanditsoptimization,policyenforcementandverification,resourceallocationandmigration,loadbalanceandstatemanagementtechnology,andNFVsecurity.Finally,thispapersummariestheadvantagesandshortcomingsofNFVtechnologycomparedwithtraditionalnetworkfunctions,introducestheapplicationscenariocasesofNFVandpredictstheresearchdirectionsofNFVinthefuture,accordingtotheETSIstandardarchitectureofNFV.