ETSI《NFV十周年技术演进》白皮书 Evolving NFV towards the next decade

ETSIWhitePaperNo.54

nextdecade

EvolvingNFVtowardsthe

1stedition–May2023

Authors(alphabeticalorder):

XuhuiCAI,HuiDENG,LingliDENG,AhmedELSAWAF,ShenGAO,ArturoMARTINDENICOLAS,YoshihiroNAKAJIMA,JanuszPIECZERAK,JoanTRIAY,XuliangWANG,BaoguoXIE,HammadZAFAR

ETSI

06921SophiaAntipolisCEDEX,France

Tel+33492944200

info@

EvolvingNFVtowardsthenextdecade2

Abouttheauthor

ThisWhitePaperhasbeenproducedasacollectiveeffortwithintheETSIISGNFV,andonitsbehalfthe

followingeditingteam(listedinalphabeticalorder):

XuhuiCAI(ChinaMobile)

HuiDENG(Huawei,ETSIISGNFVVice-Chair)

LingliDENG(ChinaMobile)

AhmedELSAWAF(Nokia)

ShenGAO(ChinaTelecom)

ArturoMARTINDENICOLAS(Ericsson)

YoshihiroNAKAJIMA(NTTDOCOMO,ETSIISGNFVChair)

JanuszPIECZERAK(Orange,ETSIISGNFVVice-Chair)

JoanTRIAY(NTTDOCOMO)

XuliangWANG(ChinaTelecom)

BaoguoXIE(ZTE)

HammadZAFAR(NEC)

EvolvingNFVtowardsthenextdecade3

Contents

Abouttheauthor2

Contents3

ExecutiveSummary5

1NFV:ashorthistory6

2Challenges,trends,andopportunitiesforNFV7

2.1Declarativeintent-drivennetworkoperations7

2.2Theriseofcontainerizationandheterogeneousinfrastructure8

2.3Autonomousnetworking,automation,andunified/soledatasource9

2.4Fragmentationoftelcocloudimplementations11

2.5Businesssustainabilityversusrapidreleaseevolutionofopensource13

2.6Hyper-distributed&full-interconnectededgedeployments13

3TowardsthenextdecadeofNFV14

3.1ContextforNFV:5Gadvanced,6Gandbeyond14

3.2APIsdevelopmentandrelationshiptoopensource15

3.3NFVmulti-cloudandmulti-technology16

3.4UnifiedNFVmanagementandorchestration17

3.5Autonomousnetworking,automation,andAI18

4Conclusionandsummary19

References21

EvolvingNFVtowardsthenextdecade4

EvolvingNFVtowardsthenextdecade5

ExecutiveSummary

NetworkFunctionsVirtualization(NFV)hasbeenthecatalystofaradicalchangetothetelecomindustry,leadingthetransitionfromthetraditionalphysical(hardware)networkapplianceintoanewsoftware-basedvirtualizednetworkfunction(VNF)era.Basedontheuseofgeneral-purpose(commodity-off-the-shelf,COTS)serversandthedeploymentofnetworkfunctionsassoftwareapplications,NFVhasbrokenthroughthetechnicalchallengesofsoftwareandhardwaredecoupling.Themigrationofnetworkfunctionsfromdedicatedphysicalappliancestodistributedcloudinfrastructurehasrevolutionizedthewaycommunicationsnetworksaredeveloped,deployed,andoperatednowadays.

In2012variousinternationalleadingtelecomserviceproviders(networkoperators)jointlyreleasedtheseminalWhitePaperaboutNFV’sconceptandvisionandannouncedthebeginningofanewerainthetelecomindustry.SincethecreationoftheETSINFVIndustrySpecificationGroup(ISG)inlate2012(thefirststandardsorganizationofthiskindinthisdomain)networkoperators,communicationstechnology(CT)vendors,informationtechnology(IT)vendors,smallandmedium-sizedenterprises(SME)andothercorecontributors(e.g.,fromopensource,academiaandresearchcommunities)havebeenactivelydiscussingandstandardizingtheNFVframework,whichhasbecomethetelcocloud&virtualizationnetworkarchitectureofreference.

ThemixtureofITandtraditionaltelecomnetworksviewpointsinNFVhavealsobroughtachallenging,yetanimportantnetworktransformationenvironment.Traditionally,networkoperatorsandCTvendorshavebecomeaccustomedtotheconsensus-basedstandarddevelopmentprocess,fromwhichproductsarethendevelopedandcommercialized.However,thescenarioofITvendorsandopensourcecommunitiesisdifferent;thesearebasedona"code-first"process,wherebycodeisfirstdevelopedandthencontributed.Thesetwowaysofdevelopingcurrenttelecomnetworkstechnologyneedtobebroughttogether,as"sidesofthesamecoin";inthisscenario,networkoperators,CTandITvendors,andopensourcecommunitiesneedtoworktogethertobridgethegapbetweenthetwoperspectivesandfacilitatebroadersupportofNFVstandards.Forinstance,whileopensourcecouldfurthersupportandimplementthestandardsasmuchaspossible,standardscouldconsiderthe"borrow-inphilosophy"totakeadvantageofthecorestrengthofopensourceinthespecifications.

TenyearsaftertheemergenceofNFV,andaftermajorinvestmentsandnetworkdeploymentsbasedonit,itistherighttimetoconsiderhowNFVcanandwillevolve.Forthis,itisimportanttounderstandandtakeactionstotherequirementsthattelecomserviceprovidersconsiderfortheirtelcocloud:1)unifiednetworkmanagement;2)useoflatestcloud-native,IT,automationandArtificialIntelligence(AI)opensourcesoftware,and3)multi-vendorinteroperabilityandmigrationamongdifferentclouds.

Buildingonpreviousachievements,thisWhitePaperanalyzesdifferentchallengesandtechnologytrends,andproposesseveralpotentialdirectionsonhowNFVcanevolveinthenextdecade.AspectsaboutAPIdevelopment,opensource,NFVmulti-cloud,unifiedmanagement,automation,andAIareconsideredaskeydriversfortheevolution.

TheWhitePaperisorganizedasfollows:section1summarizesNFV’shistory;section2recapslearnings,experiencesandchallengesrelatedtoNFVandintroducesvarioustrendsandopportunitiesinnetworktransformationthatcanplayanimportantroleforNFV.Section3developsthewayforwardforevolvingNFV.Finally,section4concludestheWhitePaper.

EvolvingNFVtowardsthenextdecade6

1NFV:ashorthistory

TheNFVconceptwasfirstproposedin2012,almostatthesametimeastheETSIISGNFVwasestablished.Thegroupstarteditsjourneyfromajointeffortamongtelecomserviceprovidersandvendors.Keyexpertswereentrustedtothedevelopmentofanewapproachtoprovidetelecomnetworksbasedonvirtualizedtechnologies.

ETSIISGNFVattractednotonlyvendorsoftelecomnetworksystems,butalsovendorsofinfrastructureandsoftwareenablingvirtualization.Fromtheverybeginning,itwasidentifiedthatajointeffortwasneededtodefinerequirementsforaninfrastructurerequiredtobeefficient,reliable,andcapable(e.g.,withaccelerationsupport)inordertobuildasolidbasefortransitioningtelecomnetworkstowardscloudsandNFV.NFV'ssuccesshighlyreliesonthiscollaborationbetweennetworkoperatorsandvendors,andtheconsensusreachedbetweenthem.

Byadoptingcutting-edgeITtechnologies,NFVhasbeenincreasinglyinfluencedbyopensourcecommunities,especiallyconsideringcommerciallyavailablenetworkdeploymentswhereinintegratedsolutionshavebeenbuiltbasedonkeyreferenceopensourceprojects.Indeed,atveryearlystagesitwasidentifiedthat,inordertorealizetheNFVfromasimpletheoreticalconcepttorealcommercialization,theETSIISGNFVneededtojoineffortswithopensourcecommunitiesaswell,togetbenefitsfrombothformalstandardsandde-factostandardsandacceleratethedevelopmentbasedonreadilyavailableopensourcebasedsolutions.ExamplesofsuchcollaborationcameinearlyduringthefirstyearsoftheISG,likethecreationoftheOPNFVwhichwastaskedtoreleaseNFVintegrationsolutionsbasedonexistingITandopensourcesoftware.Later,asthenetworkandserviceorchestrationbecameparticularlyimportantforserviceproviders,anumberofotheropensourcecommunitiessuchasOSM,OPEN-O,andONAPbuiltupontheconceptsfromNFV.

InitialstagesoftheISGfocusedoncheckingthefeasibilityofNFV,whichsubsequentlytransitionedintoformaldevelopmentofstandardsforinteroperability.Sincethen,theETSIISGNFVhaspublisheddozensofNFVspecifications.Thesehavebeengrouped,released,andevolvedthroughasequenceof"NFVReleases",inashortrecapitulation:NFVRelease1laidtheconceptsfoundation,NFVRelease2providedthefirstsetofinteroperableimplementationsolutions,andNFVRelease3enhancedtheNFVframeworkbyaddressingoperationalmatters.FromNFVRelease4,additionalsupportforcontainerizedVNFstowardsmorecloud-nativedeploymentandautomationhasbeenspecified.Finally,theongoingNFVRelease5isdealingwiththeconsolidationofvariousecosystemswhichhavehadaprofoundimpactonmanyNFVrelatedstandardsorganizationsandopensourcecommunities,including3GPP,TMForum,LFN(e.g.,Anuket,ONAP,Nephio,etc.).

Asapromoterofnetworktransformationandakeyenableroftechnologyevolution,NFVtechnologiesarecontinuouslyevolving,startingfromtheearliestLTE’scorenetworkvirtualizationbasedonvirtualmachine(VM)virtualizationtechnology,to5GnetworkclouddeploymentsbasedonOScontainervirtualizationtechnologyandwithbasiclevelofautomationcapabilities.Asamatteroffact,NFVhasplayedakeyroleindefining5G.Asanexample,the3GPPdefined5Gsystemarchitectureandthedesignof5Gcorenetworkservice-basedarchitecture(SBA)wereheavilyinfluencedbyNFV,eventoapointthatonecouldclaimthat“5GisanNFV-nativenetwork”.Today,practicallyallproductportfoliosfor5GcorenetworkdeploymentsofferedbyvendorscompriseofvirtualizednetworkfunctionsbasedonETSINFVstandards.

EvolvingNFVtowardsthenextdecade7

Recently,withtheintroductionoftheconceptofautonomousnetwork,theNFVstandardsarenotscopedtonetworkvirtualizationmattersonly(likeVMorOScontainer-basedvirtualization)butareratherextendingaswelltoothermoretransversalandmulti-facetedtechnologyareas.ExamplesaretheeffortstoconsiderAIforIToperations(AIOps)relatedservices,modelsandinterfacesintoscope,suchasintent-drivennetworkservice(NS)lifecyclemanagement,managementdataanalysis,Platform-as-a-Service(PaaS)andrelatedVNFgenericOAMfunctions.

WhilethelevelofachievementsandrealbenefitsofNFVmightnotequateamongallserviceprovidersworldwide,partlyalsoduetotheparticularusecasesandcontextswheretheseoperate,therealityshowsusthat,basedontheETSINFVarchitecture,serviceprovidershavebeenabletobuildultra-large-scaletelcocloudinfrastructuresbasedoncross-layerandmulti-vendorinteroperability.Forexample,oneoftheworld'slargesttelcocloudsbasedontheETSINFVstandardarchitectureincludesdistributedinfrastructureofmultiplecentralizedregionsandhundredsofedgedatacenters,withatotalofmorethan100,000servers.Inaddition,somenetworkoperatorshavealsoachievedveryhighratiosofvirtualization(i.e.,amountofvirtualizednetworkfunctionscomparedtolegacyATCA-basednetworkelements)intheirtargetednetworksystems,e.g.,above70%inthecaseof4Gand5Gcorenetworksystems.Inaddition,ETSINFVstandardsarecontinuouslyprovidingessentialvalueforwider-scalemulti-vendorinteroperability,alsointothehyperscalerecosystemasexemplifiedbyrecentannouncementsonofferingsupportforETSINFVspecificationsinofferedtelconetworkmanagementservicesolutions.

2Challenges,trends,andopportunitiesforNFV

2.1Declarativeintent-drivennetworkoperations

Itisbecomingapparentthatthereisgrowingcomplexityinherenttodisaggregatednetworkdeployments,duetotheintroductionofvirtualizationandcloudificationtechnologies(fromaverticalnetworkdisaggregationperspective),aswellastoofined-grainedcustomizationexperiencedinactualnetworkdevelopment.

Tocopewiththegrowingcomplexityandtosimplifynetworkoperations,moregenericmanagementsolutionsarebeingenvisionedandbecomingareality.Thiscanhelpserviceproviderscoverabroaderspectrumofusecases,bothatthenetworkdeploymentlevel,aswellasattheoperationslevelwithacommongenericmanagementtoolset.Inbothlevels,NFVtechnologiesbringmajoropportunities,notonlyinofferingaframeworkfordeployingnetworksonamoreunifiedphysicalandvirtualinfrastructure,butalsoinprovidingagenericmanagementandresourceservicesplatform.Moreover,simplificationdrivestowardsnetworkoperations’efficiencyandagility,whichappliestothenetworkitselfandtheservicesofferedoverthenetwork.Thisimprovescustomersatisfactionandtheperceptionoftelecomoperators.

Inparticular,theintroductionofdeclarativeintent-basedoperationscanplayakeyroletosimplifyNFVnetworkoperations.Thedeclarativeintent-drivenoperationonlyneedsAPItobeconsumedandexposedby/tomanagedobjects’desiredstatetomaintain.ThisshiftsmoreresponsibilitytotheAPIproducermanagementfunctionintofulfillingthedesiredstate,aswellasitdemandsadditionalorchestrationcapabilitiestobesupportedbyit.Thismoredeclarativeoperationmannerhasbeensuccessfulindiversemanagementandorchestrationsystems,likethosededicatedtomanagingOScontainersfromaninfrastructurepointofview,aswellasothersintheserviceslevelmanagement.

EvolvingNFVtowardsthenextdecade8

2.2Theriseofcontainerizationandheterogeneousinfrastructure

WhenNFVstarted,virtualmachinewasthedominantandmostmaturevirtualizationtechnologyintheindustryatthetime.Therefore,itwasanaturalchoicefortheNFVcommunitytodesignthearchitecture,models,andinterfacesaroundVM-basedvirtualizationtechnologylikethoseofferedbyKVMashypervisorlayer,OpenvSwitchforvirtualnetworking,OpenStackasvirtualinfrastructuremanagement,etc.However,NFVhas,sincetheverybeginning,theambitiontocreateavirtualizationtechnologyagnosticreferencearchitectureandassociatedsolutions;asexamples,conceptssuchas"virtualizationcontainer"andvirtualizationdeploymentunit(VDU)werecreatedtoabstractthedifferencesoftheunderlyinginfrastructure.However,abstractingdifferentvirtualizationtechnologiesisnotaneasytaskasavailableupstreamsolutionstobuildNFVhaveveryspecifictechnology-dependentfactors.

ThebenefitsofVM-basedvirtualizationtechnology,suchastheirmoredynamicmanageabilitywithrespecttolegacyhardware-basedsolutions,aswellasthegoodlevelsofisolation,securityandperformancehaveprovedtobeakeyassetinpastandcurrentNFVdeployments.ItcouldevenbesaidthatsomenetworkfunctionsbenefitgreatlybythestabilityandmaturityoftheVM-basedvirtualizationtechnologies,whichisaperfectmatchwhenconsideringthestringentlong-termsupportandmaintenancerequirementsoftelecomnetworks.

TheOScontainervirtualizationtechnology(ormorecommonlyreferredascontainers)isbecomingovertimethemainchoicebymanydevelopmentsofcloud-nativebasedmicroservicesapplications.Amongitsadvantagesarethedeploymentspeedandmuchsmallerfootprint,factorsthatcanhelpinimprovingtheresourceutilizationandloweringtheresourcesconsumption.

WhilstNFVisrapidlydevelopedanddeployedintheworld,virtualizationtechnologiesarealsoevolvingquickly.ThevirtualizationtechnologyrepresentedbymicroVM,KataContainerandunikernelcombinestheadvantagesofVMsandcontainers,whichnotonlysatisfiesthegoodlevelsofisolation,security,andperformance,butalsohasothercharacteristicssuchasflexibility,rapiddeployment,andefficientresourceutilization.Inaddition,WebAssembly(Wasm)ismoreportableandflexiblethancontainerandcanalsobeagoodchoiceasavirtualizationtechnologyforedgedevices.

AsmorenetworkoperatorsandvendorsarealreadyleveragingthepotentialofOScontainervirtualization(containers)technologiesfordeployingtelecomnetworks,theETSIISGNFValsostudiedhowtoenhanceitsspecificationstosupportthistrend.Duringthiswork,thecommunityhasfoundwaystoreusetheVNFmodelingandexistingNFVmanagementandorchestration(NFV-MANO)interfacestoaddressbothOScontainerandVMvirtualizationtechnologies,henceensuringthattheVNFmodelingembracesthecloud-nativenetworkfunction(CNF)concepts,whichisatermcommonlyreferredintheindustrynowadays.ThishasbeenachieveddespiteOScontainerandVMtechnologieshavingsomewhatdifferentmanagementlogicandresourcedescriptions.However,diverseandquicklychangingopensourcesolutionsmakeithardtodefineunifiedandstandardizedspecifications.Nevertheless,duetothefactthatbothkindofvirtualizationtechnologiescanandwillstillplayamajorroleinthefuturetofulfillthevariousandbroadsetoftelecomnetworkusecases,effortstofurtherevolvethemaswellastocomplementthemwithothernewervirtualizationtechnologies(e.g.,unikernels)areneeded.

Furthermore,drivenbynewapplicationscenariosanddifferentworkloadrequirements(e.g.,video,CloudRAN,etc.),newrequirementsfordeployingdiversifiedheterogeneoushardwareresourcesintheNFVsystemarebecomingareality.Forexample,tomeethigh-performanceVNFs,requirementsforheterogeneousaccelerationhardwareresourcessuchasDPUs,GPUs,NPU,FPGAs,andAIASICarebeingbroughtforward.Inanotherexample,tomeettheubiquitousdeploymentofedgedevicesinthefuture,

EvolvingNFVtowardsthenextdecade9

othertypesofheterogeneoushardwareresources,suchasintegratededgedevicesandspecializedaccessdevices,arealsostartingtobeconsidered.

Inhigh-performance,high-integration,andlow-costscenariossuchasAItraining,videoprocessing,andnetworksecurity,heterogeneoushardwaresuchasDPUs,GPUs,andNPUcanbeusedtoflexiblyoffloadbasicserviceandapplicationworkloads,suchasbigdataanalysis,network,storage,andsecuritydataprocessing.HeterogeneoushardwaresuchasSmartNICsandsmartcloudcardscanbeusedtooffloadvirtualswitchflowtablesorhypervisors,whichcangreatlyimprovenetworkperformancesuchaspacketforwarding,storageaccelerationandsecurityencryption.

Furthermore,currentoperatorneedsextendbeyondperformance,scalability,andflexibility,intootheraspectssuchasprivacyandsecurity.Inthatrealm,theconceptofsecureisolationandprivacyprotectionaregainingtraction.Thesenewinfrastructureoptionscannotsimplybeconsideredasanotherembodimentofexistinghypervisor-basedorOS-basedNFVIduetotheintroductionofsomefundamentalelements,suchasSecurityMonitor,andconceptssuchasencryptedmemoryspace,truststatusverification,hypervisorpartitioning,etc.Goingforward,suchsecurity-relatedelementsneedtobeconsideredasanadditionalkeybuildingblockforaddressingnewchallengingsecurityrequirementsin

NFV.

2.3Autonomousnetworking,automation,andunified/soledata

source

Theautonomousnetworktechnologyisamainstreamtransformationtrendinthetelecomindustry.Itaimstoenhancetheautomaticandintelligentoperation,administration,andmaintenance(OAM)capabilityinthewholelifecycleofthenetwork,provideendconsumersandverticalindustrycustomersa"zerowaiting,zerofault,andzerotouch"experience,supportcustomer,individual,enterpriseandnewverticalservicedevelopment,andbuild"self-configuration,self-healing,andself-optimization"capabilitiesforintelligentnetworkOAM.Manydifferentstandardsorganizations,suchasETSI,TMF,3GPP,GSMA,NGMN,andopensourcecommunities,suchastheLinuxFoundation,haveembracedwithintheirrespectivetechnicalworkingscopesthistechnologyandformulatingstandardstojointlypromotethedevelopmentofautomationforthetelecomecosystem.

Themainobjectivesoftheautonomousnetworkarediverse.Thefirstisreducingoperationalcostsanderrorscausedfrommanualoperations,andthecomplexityofsystemmanagementandmaintenancebyintroducingmorecloseloopautomation.BuildingandmaintaininganNFV-basednetworkdeploymentcanberathercomplexasthenetworkgetsmoredisaggregated.Variousanddifferentcomponentssuchasresourceorchestrationandmanagementfunctions,infrastructureplatformandmanagement,theVNFsthemselves,etc.needtobeallconsidered.Awell-designedautonomoussystemcouldhelphidethecomplexityoftheinterworkingbetweenthesecomponents,andthuseasetheworkofhumanoperators.

Thesecondobjectiveisimprovingtheefficiencyindevelopingandhelpingtoreducethetimeinlaunchingnewservices.Here,anexamplecanbetheautomationcapabilitiesofasystemthatrunsthroughandautomatesatseveralstepsintheprocesssuchassoftwareversionmanagement,integration,testing,distribution,servicedeployment,andupgradeprocesses,etc.Figure1belowillustratesthetrendwherebyatransitionoccursbetweenacase(shownontheleftside)wherefullautomationtakesplacesatselectedstepsinthelifecycleofcurrenttelecomnetworkstoacase(shownontherightside)wherefullautomationcantakeplaceateachandeverystep,thusrealizingafullend-to-endautomatedlifecycle.

EvolvingNFVtowardsthenextdecade10

Figure1:Transitiontoend-to-endautomation

Thirdly,AI,machinelearning,andothertechnologiesarebeingintroducedtohelpnetworkoperationspersonnelhandlefaultalarmsandoptimizesystemperformancemoreeffectivelybyanalyzingmassdataandbuildingmodels.

ByusingtheNFVtechnology,telcocloudmanagementhasimplementedbasicautomationofnetworkfunctiondeployment,monitoring,andmanagement.However,thetrendshowsthattelcocloudmanagementisevolvingtowardshigher-orderself-intelligentnetworking,byusingcutting-edgetechnologiessuchasbigdata,AI,anddeclarativeAPIs.Self-service,self-distribution,andself-assuredtelecomnetworkinfrastructuretosupporttelecomnetworkscanopenupthedoortomulti-service,multi-field,full-scenario,andfull-lifecycleclosed-loopself-intelligencecapabilitiesandprovideefficientmethodsforoperatorsinnetworkplanningandOAM.

Onebasisofimplementingautomationisdatamanagement.Withoutaccurate,real-time,andreliabledata,itbecomesimpossibletodrivethesystemtomakedecisionsandtakeappropriateactions,therebyhamperingtheeffectofthemanagementsystem.Thecurrentmulti-vendor,multi-componentandlayeredconstructionofanNFV-basednetworkbringsadditionalchallengestodatamanagement.Thefirstchallengeisdatadispersionandnon-standardizeddata:differentcomponentsinthesystemcollectandmaintaintheirowndataformanagementandorchestration.Furthermore,solutionsfromdifferentvendorsoropensourceprojectsusuallyhavedifferentdesignswithregardstodatacollectionfrequency,dataformat,etc.,whichmakesitharderfordatacomparison,validation,synchronizationandanalysis.Thesecondchallengeisthelimitedscopeofdatacollec