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Collaborative Content Distribution over a VNF-as-a-Service platform

Nicolas Herbaut

To cite this version:

Nicolas Herbaut. Collaborative Content Distribution over a VNF-as-a-Service platform. Networking and Internet Architecture [cs.NI]. Université de Bordeaux, 2017. English. �NNT : 2017BORD0738�.

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THÈSEPRÉSENTÉE POUROBTENIRLEGRADEDE

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Co l laborat iveContentD istr ibut ion

OveraVNF-as-a-Serv iceP latform

par

N ico lasH ERBAUT

Soutenuele13/11/2017,devantlejurycomposéde:

Présidentedujury

FrancineKRIEF,Professor...Bordeaux-INP,LaBRIUMR5800,France DirecteurdeThèse

DanielNEGRU,AssociateProfessor,HDR... Bordeaux-INP,LaBRIUMR5800,France Rapporteurs

Laurent MATHY,Professor...UniversityofLiège,Belgium TarikTALEB,Professor...AaltoUniversity,Finland Examinateurs

Liam MURPHY,Professor...UniversityCollegeofDublin,Ireland AdlenKSENTINI,AssociateProfessor,HDR...Eurecom,France MarkoVUKOLI´C,ResearchStaff Member...IBMResearch,Switzerland

CollaborativeContentDistributionoveraVNF-as-a-Serviceplatform Abstract

TheconstantriseofOver-The-TopvideoconsumptionnowadayschallengesthecurrentInternet architecture. Asanoverwhelming majorityofthebandwidthtodayisdedicatedtothedelivery ofvideocontents,InternetactorssuchasContentProviders,ContentDeliveryNetwork,Internet ServiceProvidersareforcedtooptimizetheirnetworkstosupporttheQualityofExperienceexpected bytheEnd-Users.Suchcostlyspecializednetworksparticipatetotheso-called"ossification"ofthe Internetwhich makesthearchitecturehardertoupdate,astheplacementanddimensioningoflinks and middleboxes maybehardtochangeinthefuturetosupportnewusecases.Fortunately,the trendofVirtualizatingandSoftwarizingthenetworkspushedby majorTelcooperators,vendorsand standardizationbodieshasgivenhopesthatthecomputingandnetworkinginfrastructurecanbe easilyre-purposed.TheagilitypromotedbytechnologiessuchasNetworkFunctionVirtualization andSoftwareDefinedNetworking makesitpossiblefor middleboxestobedeployedasVirtual NetworkFunctionsthatcanrunon"commercialoff-the-shelf"hardwarewhilehavingthenetwork managedbyalogicallycentralizedcontrollerdeployingnetworkconfigurationsonprogrammable forwardingdevices.

Thegoalofthisthesisistoshowhowcontentdistributioncanbecollaborativelyimprovedthanks toNetworkSoftwarization.First,weproposeCDN-as-a-Service(CDNaaS),acompletesolutionto virtualizeaContentDeliveryNetworkontopofaVNF-as-a-Serviceplatform,adoptedandevaluated atlargescaleintheFP7T-NovaEuropeanproject. Weelaborateontheinterfaces,architectureand designchoices madetoimplementtheplatformtosupportperformance,automaticscalingand re-usability.Then,weproposetwocollaboration modelsallowingthecontentdeliveryactorstowork jointlyonimprovingEnd-UserQualityofexperiencewhilefosteringahealthycompetitionandafair balanceofrevenue.Finally,westudythechallengesofNFVresourceallocationforthevCDNservice andproposeseveralheuristicsandalgorithmstooptimizetheproposedsolutioninacost-effective way.ThisthesispavesthewaytowardsacollaborativecontentdistributionallowingEnd-Usersto accesstheircontentwiththehigheststandardswhilecontributingtoasounddevelopmentofthe Internet.

Keywords:NFV,SDN,ContentDelivery,Blockchain

présentéeauLaboratoireBordelaisdeRechercheenInformatique —UMR5800 LaBRI —351,AvenuedelaLibération—33400Talence —France

ii

Distributiondecontenuscollaborativebaséesuruneplateformedefonctionsréseaux virtualiséesentantqueservice

Résumé

L’augmentationconstantedelaconsommationdevidéospardesservicesparcontournement (Over-The-Top) metà mall’architectureactuelled’Internet.Alorsqu’uneécrasante majoritédela bandepassanteaujourd’huiestallouéeàlalivraisondecontenus,lesacteursdel’Internet,telsque lesfournisseursdecontenus,lesréseauxdedistributiondecontenusetlesfournisseursd’accèssont obligésd’optimiserleursréseauxpoursupporterlaqualitéd’expérienceattendueparl’utilisateur final.Cesréseauxcouteuxetspécialisésparticipentàl’ossificationdel’Internet,rendantl’évolution desonarchitectureplusdifficileà moyenterme.Eneffet,unchoixtropspécifiquededimensionne- mentdesliensetdelalocalisationdes middle-boxespeutêtreunfreinàune miseàjourultérieure envuedusupportdenouveauxcasd’utilisation.Heureusement,lestechnologiesdevirtualisation récemmentpromuesparlesgrandsopérateursInternet,lesvendeursdesolutionsetlesorganismes destandardisation,permettentuneréelleprogrammabilitéduréseauetuneplusgrandeversatilité danslesusagesdenouveauxéquipements.Eneffet,l’agilitéapportéeparcestechnologiespermetle déploiementdeFonctionsRéseauxVirtuelles(VNF,VirtualNetworkFunctions)pouvants’exécuter surdesserveursdesérieàbascoût.QuantauSoftware-DefinedNetworking,ilrendpossibleune gestionduréseaulogiquementcentraliséepermettantlaprogrammationdescommutateurs.

L’objectifdecettethèseestde montrercommentladistributiondecontenupeutêtreaméliorée collaborativementàl’aidedelaprogrammabilitéderéseaux.Toutd’abord,nousproposonsCDNaaS, unesolutioncomplètederéseaudelivraisondecontenudéployéesuruneplateformede"fonctions réseauxentantqueservice"adoptéeetévaluéeàlargeéchelledanslecadreduprojetEuropéenFP7 T-NOVA.Nousprécisonslesinterfaces,l’architectureetleschoixdeconceptionfaitpourdévelopper laplateformeafindefournirperformance,auto-dimensionnementetréutilisabilité.Puis,nouspro- posonsdeuxmodèlesdecollaborationpermettantauxacteursdelalivraisondecontenudetravailler ensembleafind’augmenterlaqualitéd’expériencepourl’utilisateurfinal,toutenpromouvantune compétitionsaineetunerépartitionéquilibréedelavaleurajoutée.Finalement,nousétudionsles défisliésàl’allocationderessourcesvirtuellesdanslecasd’unservicevCDN,etproposonsplusieurs heuristiquesetalgorithmespermettantl’optimisationducoûtduservice.

Cettethèseouvrelavoieàunedistributiondecontenucollaborativepermettantauxutilisateurs d’accéderàleurscontenusavecunhautstandarddequalité,toutencontribuantàundéveloppement saindel’Internet.

Motsclés: NFV,SDN,Livraisondecontenu,Blockchain

Remerc iements

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iii

àDéborahetàtoutesnoséto i lespasséesetfutures

Contents

Remerciements iii

ListofFigures ix

ListofTables xi

Acronyms xiii

1 Introduction 1

1.1 ThesisContributions ... 2

1.2 ThesisOrganization... 3

2 PerspectivesinNetworkSoftwarizationandContentDistribution 5 2.1 MotivationsforSoftwareDefinedNetworking... 5

2.2 MotivationsforNetworkFunctionsVirtualization ... 7

2.3 VNF-as-a-Service:theT-NOVAapproach ... 9

2.4 NetworkSoftwarization,anopportunityforContentDistributionchal- lenges?... 16

2.5 Conclusion ... 22

3 CDNaaS:ContentDeliveryNetworkasaVNF 25 3.1 Introduction ... 26

3.2 BackgroundonexistingCDNsolutions ... 30

3.3 TheCDNaaSproposal ... 35

3.4 LinuxcontainersbenefitsforCDNaaSdeployment ... 43

vii

viii CONTENTS

3.5 CDNaaSIntegrationandValidation ... 46

3.6 ConclusionandFuturework... 54

4 AModelforContentDeliveryCollaboration:aVNF-as-a-ServicePerspective 57 4.1 Introduction ... 57

4.2 CDNaaSinISPnetwork:whichcollaboration model? ... 60

4.3 AUser-CentricCollaboration Model ... 75

4.4 Conclusion ... 88

5 DeploymentandOptimizationofVirtualContentDeliveryNetworks 89 5.1 Introduction ... 90

5.2 CDNaaSchaincomposition ... 93

5.3 CDNaaSServiceGraphEmbedding ... 100

5.4 CDNaaSDynamicSLAssupport ... 111

5.5 Conclusion ... 118

6 Conclusionandperspectives 121 A RésuméenFrançais 125 A.1 MotivationpourlavirtualisationduCDN ... 125

A.2 CDNaaS:l’Implémentationderéférence... 126

A.3 DéploiementdeCDNaaSdansleréseauopérateur... 126

A.4 Sessionsdecontenuecentréessurl’utilisateur ... 127

A.5 AllocationderessourcepourlesVNF... 127

A.6 Conclusion ... 128

B Listofpublications 129

Bibliography 131

L istofF igures

2.1 SDNFunctionalarchitecture... 6

2.2 HighlevelviewofT-NOVASystemArchitecture... 11

2.3 Cross-Chronologyoftechnological mutationsbetweenContentDistribution Services,andISPInternetaccessoffers... 17

2.4 PeakPeriodTrafficComposition... 19

3.1 the20biggestAutonomousSystemsperpublicpeeringbandwidthcapabili- ties(DataexportedfromthePeeringDBAPI)... 26

3.2 TradeoffsforContentDeliveryNetworksTechnologies. ... 27

3.3 High-levelfunctionalbreakdownofaContentDeliveryNetworkService... 30

3.4 ETSITISPANfunctionalarchitecture ... 31

3.5 ImpactofDNSserveronAirbnbserverselection ... 32

3.6 ImpactofDNSserveronYoutubeserverselection ... 33

3.7 HighLevelArchitectureofCDNaaS ... 37

3.8 InternalArchitectureofVMGclusters... 40

3.9 ComparisonbetweenT-NOVAandSwiftStackabstractions... 41

3.10 ArchitectureoftheIngestion... 42

3.11 ComparisonbetweentheTraditionalVNFLifecycleandtheagilelifecycle.. 44

3.12 HighLevelarchitectureforaCDNaaSrunninginaNFV-as-a-Serviceplatform 48 3.13SequenceDiagramofCDNaaS,thevCDNCustomerinteractswiththeT-NOVA Marketplacetocreatetheservice,andwiththeElement ManagerforService Configurationand monitoring. ... 49

3.14ImpactoftheVMGHTTPfilter/actionoverheadoncontentdelivery ... 51

3.15ImpactoftheloadbalancingontheVMGdeployment... 52

3.16 End-to-endevaluationofthecontentdeliverycomponents ... 53 ix

x ListofFigures

3.17 TranscodingPerformances... 54

4.1 DeployementofaCDNOverlayusingCDNaaS ... 61

4.2 CDN,ISPand Marketplaceinteractions ... 63

4.3 ThevCDNCustomerprogramsCDNaaS’CROtoorchestratebothinternal resources(VMGandvSTR)andthevCDNOverlayNetworkController.... 64

4.4 OptimalityzonefortheCDN-as-a-VNFstrategy(5) ... 68

4.5 OnlineCDNaaS managementresults... 72

4.6 CompetitionLociinOTTcontentdelivery. ... 75

4.7 Stakeholdersinteractionsinthecontentsession. ... 76

4.8 Blockchain-based modelforcollaborativevideodelivery. ... 78

4.9 CDN,CDNaaSandµCDNservicesdeployedinanISPnetwork... 82

4.10 RespectiveTEsshareforCDC ... 85

4.11 Averagepriceforcontentdelivery... 86

4.12 Testbed ... 86

4.13 Performanceandscalabilityexperiment... 87

5.1 Canonical Model... 95

5.2 ConcreteImplementationoftheCDNaaSServiceusingSFC ... 96

5.3 BuildingatreewithServiceEdges. ... 97

5.4 2Service-isomorphicgraphs... 97

5.5 PhaseI:AssigningvMGtoCG ... 98

5.6 PhaseII:AssigningvStreamertovMG ... 98

5.7 PhaseIII:PartialEmbeddingwithoutCDN,AssigningCDNtoVMG ... 98

5.8 MappedVCDNService ... 100

5.9 Illustrationofour mapping"genotypes", mutationandbreedingprocedures. 104 5.10CostComparisonofserieofsuccessiveembeddingperformedontheGeant Topology ... 108

5.11 Comparisonofsolverscomputationtime ... 109

5.12 Comparisonofsolversperformance ... 110

5.13 Adaptivestrategyselectionalgorithm ... 110

5.14 VCDNfivestepsofdeploymentandoperation ... 112

5.15Step1–Datacollectionshowingatypical mixtureofASsatapeeringpoint . 112 5.16Step2–Forecast,SLAandDiscretizationevaluations ... 114

5.17 Differentdiscretizationparameters... 115

5.18SLAgeneratedfromdiscretizedpredictions ... 115

5.19Step3–DiscretizationandSLAGeneration ... 115

5.20Step5–Dynamiccost-awarescheduling... 116

5.21ExampleoftheevolutionofthecostofServiceEmbeddingwithSLAgenerated from4ISPs,4legacyCDNpeeringpointsover24h... 117

5.22 Evaluationimpactofserviceoptimizationanddiscountpolicy ... 117

L istofTab les

2.1 MainchallengesfacedbyISPandproposedsolutionsdevelopedinthisthesis 21

2.2 SWOTAnalysisofadoptingtheproposals(1),(2)and(3)ofTable2.1 ... 22

2.3 Listof majorstrategicopensourceSDNandNFVprojectsorinitiativeswhere Telcosassumedirectorpositions^a... 23

3.1 RequirementsforCDNaaS ... 36

3.2 ETSITISPANandCDNaa+T-NOVAFunctionalArchitectureComparison... 38

3.3 RESTAPIusedtoconfiguretheVMGFiltersandActions ... 39

4.1 Notationsandestimatesforuse-case1... 65

4.2 Profitability matrixcontainingEarningsandCostsforCDNandISPforeach collaborationscenario... 66

4.3 ComparisonofdifferentCDNdeployment models... 71

5.1 CDNaaSSLAdescription ... 94

5.2 Notations ... 101

5.3 #ofServicesgraphsandcomputationtime ... 106

5.4 CostParameters ... 106

5.5 GeneticAlgorithmparameters... 108

xi

Acronyms

ALTO Application-LayerTrafficOptimization. API ApplicationProgrammingInterface. AS AutonomousSystem.

CAPEX CapitalExpenditure. CBC ContentBrokeringContract. CDC ContentDistributionContract.

CDCS ContentDeliveryServiceDescription. CDN ContentDeliveryNetwork.

CDNaaS CDN-as-a-Service. CDNi CDNInterconnection. CLC ContentLicensingContract. CP ContentProvider.

CPE CustomerPremisesEquipment. CPU CentralProcessingUnit.

CRO CachingandRoutingOrchestrator. DNS DomainNameServer.

DPDK DataPlaneDevelopmentKit.

DRM DigitalRights Management. EMS Element ManagementSystem. EU End-User.

HTTP HypertextTransferProtocol. HTTPS HTTPSecure.

ILPIntegerLinearProgramming. IOTInternetofThings.

ISPInternetServiceProvider.

IVMInfrastructureVirtualizationand Manage- ment.

IXPInternetExchangePoint.

NFV NetworkFunctionVirtualization.

NFVMANO NFV ManagementandOrchestra- tion.

NFVI NetworkFunctionVirtualizationInfras- tructure.

NFVI-POP NetworkFunctionVirtualizationIn- frastructurePointofPresence.

xiii

xiv ACRONYMS NMS Network ManagementSystem.

NS NetworkService.

NSD NetworkServiceDescriptor. NSP NetworkServiceProvider. OPEX OperationalExpenditure. OSPF OpenShortestPathFirst. OTT Over-The-Top.

P2P Peer-to-peer.

PBFT PracticalByzantineFaultTolerant. POP Point-of-presence.

QoE QualityofExperience. QoS QualityofService.

SDN SoftwareDefinedNetworking. SFC ServiceFunctionChaining. SLA ServiceLevelAgreement. TE TechnicalEnablers. TeNOR T-NOVAOrchestrator. URL UniversalResourceLocator. vCDNVirtualCDN.

vCPUVirtualCPU.

VDU VirtualDeploymentUnit. VIM VirtualInfrastructure Manager. VM Virtual Machine.

vMGVirtual MediaGateway. VNE VirtualNetworkEmbedding.

VNF VirtualNetworkFunction.

VNFC VirtualNetworkFunctionComponent. VNFD VirtualNetworkFunctionDescriptor. VNFM VirtualNetworkFunction Manager. VOD VideoonDemand.

vStreamerVirtualStreamer. WAN WideAreaNetwork.

WICM WideAreaNetworkInfrastructureCon- nection Management.

C

1 Introduct ion

For manyyearsnow,theconsumptionofOver-The-Top(OTT)video-on-demandstreaming serviceshasbeenconstantlyincreasing.In2016,suchservicesaccountedfor morethan 55percentofpeakInternettraffic,andthatpercentageisstillgrowing[SANDVINE,2016], expectingtoreach morethan80percentin2020.Shiftsincontentdistributionhavethus becomenecessary,leadingtoContentDeliveryNetworks(CDNs)andotherapproaches thataccommodateOTTcontent.

Thecontentdistributionecosystemthathasemergedduringthepastdecadeisstruc- turedaroundavarietyofactorsalongavaluechain.Someactorsfulfillatechnicalrole,such asInternetServiceProvider(ISP)andCDNoperators,whereasothersare moreoriented towardbusiness,suchasContentProvider(CP).

Thisvaluechainhasgovernedthedemocratizationofonlinevideos,butthecurrent surgeofOTTIP-basedstreamingreshufflesthedeck.Specifically,ISPsareleftbehind, becausetheydonotbenefitfromtheaddedvalueofcontentdelivery(eventhoughthey arestillsupportingheavyinfrastructurecosts),andCDNoperators mustbuildincreasingly expensivenetworkstotargetaworldwideaudience.Atthesametime,CPsandowners arebenefitingfromgrowthintheonlinevideos market.Inthisecosystem,collaboration betweenactorsisthekeytotackletheexistingchallenges,withaspecificfocusonfinding synergies.

ISPsaresolicitedbyCPsorCDNstoinstallstreamingapplianceswithintheirnetworkto delivercontentdirectlytotheirusers(e.g.,NetflixOpenConnect),reducingthenumberof hopsaswellasinter-autonomous-systemtraffic[Pathan,2014a].Thesesolutionsreduce bothCDNandISPcostsandeasetechnicalcooperationbyenablingjointcontrolofthe delivery[Böttgeretal.,2016].However,thecollaborationisnotfair,becausetheISPdoes notbenefitfromtherevenuegeneratedbytheCP.Furthermore, manycompaniesarenow consolidatingthedifferentrolesofthevaluechainintooneentity[Hallingbyetal.,2016].

1

2 CHAPTER1.INTRODUCTION Althoughthis mightfacilitateend-to-endoperations,itcanhinderinnovationandraisethe barrierfornewcomersonthe market.

Atthesametime,existingtechnologiesinitiallydevelopedtosupportITservicessuch ascloudcomputingandnetworkprogrammabilityarestartingtoemergeintheTelecom worldas“networksoftwarization”:

•SoftwareDefinedNetworking(SDN)isthelatestincarnationofalonghistoryof effortsto makecomputernetworks moreprogrammable[Feamsteretal.,2014],and paradoxicallyrevisitsideasfromearlytelecomnetworksrelatedtotheseparationof controlanddataplanestosimplifynetwork managementandthedeploymentofnew services.

•NetworkFunction Virtualization(NFV) wasintroducedin2012 bythe Euro- pean Telecommunications StandardsInstitutethrough aseminal white pa- per[Virtualisation,2012].TheNFVconceptaimsatcreatingareferencearchitecture andastandardizedapproachtoachievecarriergradevirtualizationoncommod- ityserversofexistingnetworkfunctionsthatarecurrentlyhandledbyhardware middleboxes.

Webelievethattheseemergingparadigmsofferaninterestingtechnologicalplatformto addressthechallengesfacedonthecontentdeliveryfront.

Basedontheseobservations,thevirtualizationofthecontentdeliveryfunctionseems tobeapromisingapproachtoaddresstheaforementionedissues.Inthisthesis,westudy howacollaborationbetweenISPs,CPsandCDNscenteredonaVirtualCDN(vCDN)can takeplacetoimproveEnd-UsersQualityofExperiencewhilereducingcostsandfairly allocatingprofitalongthecontentdistributionvaluechain.Bellow,weoutlinethespecific contributions madeinthisthesis.

1 .1 Thes isContr ibut ions

Inthecontextofpromotingcollaborationforcontentdelivery,oursignificantcontributions are:

1.First,ascurrentadvancesonnetworksoftwarizationallowdeployingVirtualNetwork Functionsinanoperatornetwork,weproposethevirtualCDN-as-a-Service(CDNaaS) concept.ItallowsacustomertodeployitsownimplementationofaCDNasaVirtual NetworkFunction(VNF)attheedgeoftheISPnetwork. Wepresentitsarchitecture anddesign,aswellastheintegrationintoanopen-sourceNFV Managementand Orchestration(NFV MANO)stackdevelopedwithintheT-NOVAEuropeanproject. Weevaluateeachcomponentaccordingtoasetofrequirementsandthesystemasa whole,atlargescale. Wealsodiscussanddemonstratehowautomationandscalability canbeachievedeasilywiththeuseofLinuxcontainers.

1.2.THESISORGANIZATION 3 2.Second,asthebenefitsforavirtualCDNdependsonitsadoptionbycontentdelivery actors,westudyhowa mutuallyprofitablecollaborationcanbeestablishedbetween ISPandCP/CDNoperatorsandpresentthearchitectureandvirtualizationtargets foraCDNaaS-baseddeployment. Weadvocateforspecifyingtheservicethrougha high-levelServiceLevelAgreement(SLA)preservingtheconfidentialityoftheISP Network. Wethenanalyzethecurrentcollaborationschemesand modelthemusing gametheoryinordertofindtheconditionsforwhichCDNaaSisoptimal,considering arealisticpricing model.

3.Inordertocomplementtheproposed model,asthecontentdeliveryvaluechainis evolvingwiththeriseofOTTservices,weextendourproposaltotheEnd-User(EU). Weproposeauser-centric modelthatconsiderseachvideoviewingasacooperative effortbetweenseveralactors.Tothisend,abrokering mechanismisforeseenusing theBlockchainandSmartContractsto mixand matcheachstakeholderthatcan providetheadequateQualityofExperience(QoE)totheEUwiththelowestprice.The proposalisevaluatedwitharealimplementationandadiscussiononthescalability andgovernanceistriggered.Ourfindingssuggestthatsuchabrokering mechanismis feasible,giventhatsignificantprogressesonBlockchainscalabilityare made. 4.Finally,whiletheCDNaaSconceptseemspromising,deployingitonISPnetworkhas

practicalimplications.Afterrecallingthe mainaspectsofthegeneralVNFresource allocationproblem,weproposeasolutionforeachsub-step. Newalgorithmsare presentedto(1)generatetheServiceFunctionsChaincorrespondingtoavCDNSLA, (2)realizetheembeddingofavCDNserviceontheISPphysicalnetworkand(3) scheduletheservicewhilesupportingDynamicSLAs. Ourresultsindicatethatto reducethehostingcostofanSLAinitsnetwork,ISPsshouldputinplaceadiscount pricing modeltoincentiveitsclientstogeneratelongerlastingSLAs.

1 .2 Thes isOrgan izat ion

Therestofthethesisisorganizedasfollows.Chapter2overviewsthe mainideasofnetwork softwarizationandsuggeststhatitcouldbethenextevolutionofthetechnologicalmutation forISPstosolvecontentdistributionissues.Chapter3introducestheproposedconcept ofCDNaaSandhighlightsitsdeploymentontopofanNFVplatform[Rebahietal.,2016]

whileChapter4presentstwocollaborationschemesleveragingCDNaaStargetingcostre- ductionandQoEimprovements[Herbautetal.,2016][HerbautandNégru,ress].InChap- ter5,westudytheresourceallocationproblemforavirtualCDN[Herbautetal.,2017b]

[Herbautetal.,2017a]beforeconcludingandpresentingpointerstodirectionsoffuture workinChapter6.

C

2 Perspect ivesinNetwork Softwar izat ionandContent

D istr ibut ion

SoftwareDefinedNetworking(SDN)andNetworkFunctionVirtualization(NFV)arediffer- entexpressionsoftheoveralltransformationtrendtowardnetworksoftwarization,whichis deeplyimpactingandbridgingtheTelecomandITindustries[FreemanandBoutaba,2016]. Thisnewparadigmpromotessoftware-controlledtreatmentofflowsinthenetworkand theorchestrationofresourcesto meettheneedsofcustomerapplicationsinaconverged networkandcloudinfrastructure.

Inthischapter,wepresentanoverviewofnetworksoftwarizationtechnologiesand explainwhattheexpectedbenefitsare. Wethendetailaconcreteimplementationofa convergedNFVplatformthataddsanewbusinessperspectivetothetechnologythanksto aninnovativeconceptof Marketplace. Weconcludethischapterbydescribingtheevolution ofcontentdistributiontechnologiesanddiscussingwhataretheopportunitiesbroughtby networksoftwarizationtoaddresstotheoutstandingchallengeslinkedtotheriseofon-line multimediaentertainment.

2 .1 Mot ivat ionsforSoftwareDefinedNetwork ing

Today,distributedcontrolandtransportprotocolsareakeytechnologyallowinginformation totravelaroundtheworld.ProtocolssuchasOSPFandBGParecentraltotheconfiguration oftheirnetworkbyInternetServiceProviders(ISPs).

Theysufferhoweverfromseveralproblems.Theyarenotablyhardto managesince ISPsneedtoexpresshigh-levelpoliciesinlow-levelandvendorspecificfashion.Another difficulttaskistosupporthighlydynamicenvironmentswheretrafficsurgesandfaults areverycommonandneedtobeaddressedinatimely manner. Forthat,thegoalof havingautomaticreconfigurationandresponse mechanismsareverydifficultincurrent IPnetworks. Moreover,thefactthatnetworksareverticallyintegrated mixingdata-plane

5

6 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION andcontrol-planefunctionalitiesinthesamedevice makesinnovationsverydifficultto roll-out.ForexampleregardingIPv6,despitetheexhaustiononIPv4addressesandthefact thatRFC2460waspublishedin1998,adoptionisstillverylowreachinglessthan20%ofall querieshandledbyGoogleSearchengine¹

Network App l icat ion

SDN Contro l ler Forward ing Dev ices

NorthboundInterface

SouthboundInterface

Control Plane

Data Plane

.

Figure2.1:SDNFunctionalarchitecture

Drawingontheseobservations,theneedfor moreflexibleindustrialnetwork manage- menttechnologiesgained momentum.SDNisanemergingparadigmthatgiveshopein changingtheabove-mentionedlimitationsofthenetwork.Itbreakstheverticalintegration byseparatingthecontrollogic(thecontrolplane)androutersandswitchthatforward thetraffic(thedataplane)(Figure2.1).Inthiscontext,Networkswitchesbecomesimple forwardingdevicesandthelogicisimplementedinalogicallycentralizedcontroller.The SDNControlleristhecentrallayerthatisresponsibleforreceiving(throughitsnorthbound interface)thehigh-levelpoliciesexpressedassoftwareintheNetworkApplicationand translatethemtolow-levelforwardingrulesdeployed(throughitssouthboundinterface) ontheForwardingdevices.

Evenifthetechnologicalfragmentationthenorthboundinterfaceisstillanopenissue andissubjecttoafiercecompetitionfromSDNControllerprojects(seeTable2.3),the southboundinterfaceisstandardizedde-factobytheOpenNetworkFoundation’sOpen- Flow[McKeownetal.,2008].Supportedby majordevicesvendorandsoftwareimplementa- tion(e.g.OpenvSwitch[Pfaffetal.,2015]),itisanundeniablecommercialsuccessdriving theadoptionofSDN.

EveniftheSDNprinciplecanbesubjecttoarchitecturalinterpretation,iscanbereduced tofouressentialpillars[Kreutzetal.,2015]:

•controlanddataplanesaredecoupled

1https://www.google.com/intl/en/ipv6/statistics.html

2.2. MOTIVATIONSFORNETWORKFUNCTIONSVIRTUALIZATION 7

•Forwardingdecisionsareflow-basedinsteadofdestinationbased,asallpacketsofa flowreceiveidenticalservicespoliciesattheforwardingdevice

•Controllogicis movedtoanexternalentity,theSDNController(alsocalledthe NetworkOperatingSystem)

•thenetworkisprogrammablethroughsoftwareapplicationsrunningontheNOS Theexpectedbenefitsaresimplerandlesserrorpronenetworkpolicies modification thankstohigh-levellanguageandsoftwarecomponentscomparedtolow-leveldevice- specificconfiguration.Interestingly,acontrolprogramcanreacttospuriouschanges whethertheycomefromchangeinthenetworkstateorfrombadlow-levelrulesdeployed onthedevices.Finally,SDNoffersaglobalknowledgeofthenetworkstatewhichsimplifies thedevelopmentandallowsforcreating moresophisticatednetworkingfunctionsand services.

EvenifSDNscalabilityissometimessubjecttodiscussion,especiallyregardingcon- trollerscalability,flowinitiationoverhead,resiliencytofailures,thelackofnorthboundstan- dardizationandnetworkprogrammingand managementcomplexity[Yeganehetal.,2013], thoseproblemsarenotfundamentallyspecifictoSDNandcouldbeovercomewithout losingitsbenefits.SeveralindustrialsuccessstoriesfollowingtheadoptionofSDNinawide rangeofnetworkingproblemsaredocumentedinresearchfromsoftwaredefined WAN [Jainetal.,2013],todata-centernetworking[Singhetal.,2015]torecentdeploymentatthe edge[Yapetal.,2017].

Theprogrammability modelofOpenflowalsosuggeststhatSDNisnotyetcapableof handlingeverynetworkinguse-case. Despiterecentsolutionsproposedtoimproveits processingcapabilitiessuchasP4[Bosshartetal.,2014]andPMP[Pontarellietal.,2017],it isnotclearwhich middleboxcanbereplacedbySDN-programmablehardware.Ifsimple state-fullnetworkfunctionssuchasFirewall[Suhetal.,2014]canbeimplemented, more complexprocessingsuchasVideoTranscodingandstorage-intensivefunctionssuchas cachingareoutofreachforSDN.Indeed,forwardingdevicesshouldbefunction-agnosticto keephardwarepricesdown,andspecializedprocessingmaynotbeavailable.Forthisreason, NFVisperceivedastheotherpromisingparadigmofnetworksoftwarization,allowing networkfunctionstobevirtualizedtoreplace middleboxesbysoftware.

2 .2 Mot ivat ionsforNetworkFunct ionsVirtua l izat ion

ThissectionisabriefoverviewofNFV,whichillustratesthe main motivationsbehindthis newservicearchitecture[Mijumbietal.,2016]. Moredetailsaboutthestandardcompo- nentsincludingtheOrchestration managementandtheInfrastructureVirtualizationand Management(IVM)arecoveredinthepresentationofarealimplementation,theT-NOVA project,inSection2.3.

8 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION Today,serviceprovisioningintheISPinfrastructurereliesheavilyonthedeploymentof middleboxes,eachofwhichperformsadifferentNetworkFunction.Theyaredesignedfrom costlyspecializedhardwaretosupportthecarrier-gradespeedandstabilityrequiredinthe Telcoworld.Evenifthis modelprovedefficientinsupportingtheirnetworkuntiltoday,the currentneedtodeploynewservicesquicklyforcedISPstoreconsiderit.

Middleboxesproductcyclesareverylongandimpedeinnovationsfrombeingquickly rolled-out. Middleboxesplacementisaheavyprocedurethatrequiresfine-tuningand complexnetworkconfigurationupdates.Forthisreason,itparticipatestotheso-called ossificationoftheInternetinfrastructure[Counciletal.,2001]. Giventhefactthatthe numberof middleboxesisroughlyequivalenttothenumberofrouters[Sherryetal.,2012], itrepresentsaveryimportantshareinISPsCapitalExpenditure(CAPEX)andOperational Expenditure(OPEX).

TheconceptofNFV²wasintroducedin2012[ETSI,2012]fromaconsortiumofISPs willingtospecifytherequirementsforthedeploymentofNetworkFunctionsassoftwareon Commercialoff-the-shelfhardware.Ontopoftheobviousgoalofcostreduction,several interestingfeaturesareexpectedfromthisapproach.

First,asaruleofthumb,sinceno manufacturingorhardwareconceptionisinvolved, innovationhappensfasterthroughsoftware.Asacorollary,VirtualNetworkFunction(VNF) providerscollaborateeasilyonsoftwarethroughtheadoptionofopen-sourcesoftware development models[HippelandKrogh,2003].VNFproviderscooperateand mutualize theireffortinsolvingcommongoalsandreachbettersoftwarequality,faster.Forexample in2016³theopenvSwitchproject(anessentialbuildingblockforbothSDNandNFV)was transferredfromVMWaretotheLinuxFoundationwithlargecorporatecontributors(Cisco, Ericsson,Huawei,HP,IBM,Intel,RedHatandVMware).Thankstoitsrobustfoundations, theprojectisusedbyvendorsintheirvNFimplementationwithoutrequiringacomplete rewriteofthe middleware^4,5.Second,thedeploymentofservicesis moreflexiblewithNFV, assharedphysicalresourcescanbeusedtosupportdifferentnetworkfunctions.VNFcanbe instantiatedinanyNFV-capableenvironmentand migrateddependingontheneed.Third, capacityprovisioningcanadaptdynamicallydependingondemand.VNFscanincrease theirperformancebyscaling-outandreducetheirfootprintthroughscaling-in.

ThemainconcernsregardingNFVisitsabilitytoliveuptoitspromiseofinteroperability andeasyresource management.Thiscouldbeachievedintwodistinctways:(1)the main actorscancollaborateonanopen-sourceprojectuntilitbecomesthedefactostandard (e.g.theOPNFVproject⁶promotestheintegrationonupstreamprojectsintoacommon)

2http://www.etsi.org/technologies-clusters/technologies/nfv

3https://www.linuxfoundation.org/press-release/open-vswitch-joins-linux-foundation-open- networking-ecosystem/

4Thesame modelcanalsobevalidwhenconsideringsoftwaresupportforhardwareenhancementslike DPDK,whichwasinitiallydevelopedbyIntelbutisnowalso managedasaLinuxfoundationproject

5otherexamplesexist,suchaspfSenseforsecurity,opensipsforsessionbordercontrollers

6https://www.opnfv.org/

2.3. VNF-AS-A-SERVICE:THET-NOVAAPPROACH 9 and(2)sinceETSIgoalwithNFVisnottoproducestandardsbutrequirements,liaisonwith StandardsDevelopingOrganizationsaredeveloped⁷.

AnotherriskunderminingtheNFVadoptionisthefearthatsoftwareperformancewould not matchline-raterequirementsofISP.Toovercometheseconcern,severalinitiativeaims at makinghardwareaccelerationavailabletoVirtual Machine(VM)throughtheNetwork FunctionVirtualizationInfrastructure(NFVI)layer.SR-IOV[Dongetal.,2012]allowsby- passingthevirtualizedNICprovidedbytheHypervisorbyusingdirect memoryaccess. Inthiscase,however,VMcannotbe migrated,whichreducestheflexibility.UsingFPGA SoC-basedComputeNodes[Karrasetal.,2016]orGPU-enhanced[Paglierani,2015]node canalsoimproveperformances,atthepriceofanhighspecializationoftheserver⁸. A pragmaticapproachcombiningphysicalfunctionswhenrequiredandVNFwhenpossibleis aviableoptionwhileperformanceisstillanissueontoday’sserver.Thistechniquewasused byonthefirstsuccessfulfieldstudyofvirtualHomeGateways[CantóPalancaretal.,2015], [Proençaetal.,2017].

ThankstotheincreasednetworkflexibilityinducedbySDNandthepossibilitytodeploy virtualappliancesthroughNFV,theyareperceivedaskeyenablersallowingISPstoupgrade theirinfrastructuretosupportnewservices,especiallyrelatedtocontentdistribution.In thenextsection,wedigdeeperintotheintegrationofNFVandSDNbydescribingthe architectureofarealNFVplatform,T-NOVA.SinceT-NOVAis MANO-compliant, mostof theconsiderationspresentinthefollowingsectionapplytootherNFVimplementations, listedinTable2.3.

2 .3 VNF-as-a-Serv ice :theT -NOVAapproach

In this section, we briefly describe all the relevant aspects of the T-NOVA project[Xilourisetal.,2015]that wereusedtodeployandevaluateourcontributions. ThecontentofthissectionwasadaptedfromcitedT-NOVAdeliverablesandcitedpartner papers.

T-NOVA,“NetworkFunctionsas-a-ServiceoverVirtualizedInfrastructures”isaEuropean FP7Large-scaleIntegratedProject,whoseprimaryaimisthedesignandimplementation ofa management/orchestrationframeworkfortheautomatedprovision,configuration, monitoringandoptimizationofNetworkFunctions-as-a-Service(NFaaS)overvirtualized NetworkandITinfrastructures.T-NOVAleveragesandenhancescloud managementar- chitecturesfortheelasticprovisionandre-allocationofITresourceshostingNetwork Functions.ItalsoexploitsandextendsSDNplatformsforefficient managementofthe networkinfrastructure.

TheT-NOVAframeworkallowsoperatorstodeployvirtualizednetworkfunctions,not onlyfortheirownneeds,butalsotoofferthemtotheircustomers,asvalue-addedservices.

7https://portal.etsi.org/tbsitemap/nfv/nfvliaisonmatrix.aspx

8thissolutionhasalsoberecentlyadoptedbycloudproviders:https://aws.amazon.com/ec2/elastic-gpus/

10 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION Virtualnetworkappliances(gateways,proxies,firewalls,transcoders,analyzersetc.)canbe providedon-demand“as-a-Service”,eliminatingtheneedtoacquire,installand maintain specializedhardwareatcustomerpremises.

LeveragingthisNFaaSconceptandinordertofacilitatetheinvolvementofdiverseactors intheNetworkFunctionVirtualizationsceneaswellastheattractionofnew marketen- trants,T-NOVAintroducesanovelconceptof“NFV Marketplace”,inwhichnetworkservices andFunctionsofferedbyseveraldeveloperscanbepublishedandbrokered/traded.The NFV Marketplaceenablescustomerstobrowseandselectservicesandvirtualappliances thatbest matchtheirneeds,aswellasnegotiateServiceLevelAgreements(SLAs)andbe chargedundervariousbilling models.AnovelbusinesscaseforNFVisthusintroducedand promoted.

2 .3 .1 Overa l lArch itecture

TheT-NOVAsystemarchitecture[Kourtisetal.,2017]inheritsthe majorityofitsconcepts fromthegenericETSINFVISGarchitectural model[ETSI,2013a]andexpandsitwithspe- cificadd-onfeatures.TheT-NOVAarchitectureencompassesfourkeyarchitecturallayers (asshowninFigure2.2):

•TheNFVIlayerconsistsofbothphysicalandvirtualnodes(high-volumeservers, Virtual Machines,storagesystems,switches,routersetc.)onwhichthenetworkser- vicesaredeployed;TheT-NOVAplatformwasdeployedthrough3NetworkFunction VirtualizationInfrastructurePointofPresences(NFVI-POPs)inGreece,Portugaland Germany.

•TheNFVI Managementlayerincludestheinfrastructuremanagemententities:Virtual Infrastructure Manager(VIM)andthe WideAreaNetworkInfrastructureConnection Management(WICM).T-NOVAadoptsanOpenStack⁹cloudoperatingsystemfor controlofthecomputeanddata-centerassetsandOpenDaylight¹⁰forthecontrolof thenetworkinfrastructure(mostofwhichisSDN-based);

•TheOrchestrationlayerisbasedontheT-NOVAT-NOVAOrchestrator(TeNOR)Or- chestrator[Rieraetal.,2016]andalsoincludesa“NetworkFunctionStore”whichisa repositoryforallpublishedVNFs.TheOrchestrator,alongwiththeNFVI Management layerscomprisetheT-NOVANFV ManagementandOrchestration(NFV MANO)stack;

•Finally,theMarketplacelayercontainsallthecustomer-facinginterfacesandmodules, whichfacilitate multi-roleinvolvementandimplementbusiness-relatedfunctionali- ties.

9https://www.openstack.org

10https://www.opendaylight.org/

2.3. VNF-AS-A-SERVICE:THET-NOVAAPPROACH 11

Figure2.2:HighlevelviewofT-NOVASystemArchitecture

Thethreefollowingsectionspresentthefunctionaloverviewandarchitecturedetailson eachoftheselayers.

2 .3 .2 NFVIManagementLayer

T-NOVA’sInfrastructureIVMlayer[T-NOVAConsortium,2016a]providestherequiredhost- ingandexecutionenvironmentforVNFs.Theoveralldesignofthelayerisdrivenbya varietyofrequirementssuchasperformance,elasticityetc.

12 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION 2.3.2.1 FunctionalOverview

TheIVMincorporatesanumberofkeyconceptsthatinfluencetheassociatedrequirements andarchitectureforthelayer:

•TheIVMsupportsseparationbetweencontrolanddataplanesandnetworkpro- grammability.TheT-NOVAarchitectureleveragesSDNfordesigning,dimensioning andoptimizingcontrol-anddata-planeoperationsseparately,allowingcapabilities fromtheunderlyinghardwaretobeexposedindependently.

•TheIVMisbasedaroundtheuseofclustersofcommoditycomputingnodesincloud computingconfigurationstosupportinstantiationofsoftwarecomponentsinthe formofVMsforNFVsupport,offeringresourceisolation,optimizationandelasticity.

•TheIVMexposesthenecessaryinterfacestosupportappropriateintegration.The externalinterfacesprovideconnectivitywiththeT-NOVAOrchestrationlayerwhile theinternalinterfacesprovideconnectivitybetweentheinternaldomainsoftheIVM toensuretherequestsforthecreation,deployment, managementandterminationof VNFservicesandtheirhostVMscanbeexecuted

2.3.2.2 Architecture

TheVIM managesboththeIT(computeandhypervisordomains)andnetworkresourcesby controllingtheabstractionsprovidedbytheHypervisorandInfrastructurenetworkdomains. Italsoimplements mechanismstoefficientlyutilizetheavailablehardwareresourcesin orderto meettheSLAsofNetworkServices(NSs).TheVIMisalsoplaysaroleintheVNF lifecycle management.Additionally,itcollectsinfrastructureutilization/performancedata andto makethisdataavailabletotheOrchestratorinordertogenerateusage/performance statistics,aswellastriggeringscaling.

Itiscomposedofthefollowing modules:

•TheWANInfrastructureConnectionManager providesthelinkbetween WANcon- nectivityservicesandtheNFVIhostingVNFsincludingconnectivitytoNSsallocated in morethanoneNFVI-POP.

• TheVIMComputeControlprovidesanappropriatedperformancelevelforVNFs.

•TheVIM HypervisorControlimplementshardwareresourceabstraction,virtual resourcelifecycle management mechanisms.

•TheVIMNetworkControlimplementsanSDNapproachtoprovidenetworkvirtual- izationcapabilitiesinsideaNFVI-POP.Itsupportstransporttunnelingprotocolsof L2packetsoverL3networks,toassistthe WICMinsettingupthecommunication/

betweendifferentNFVI-POPs.

2.3. VNF-AS-A-SERVICE:THET-NOVAAPPROACH 13 Each moduleisresponsibleforcollecting metricsand makethemavailabletotheor- chestratorlayerthroughtheappropriateagents.

2 .3 .3 Orchestrat ionLayer

AnOrchestratorPlatformisacentraltechnologycomponentinenablementofNetwork FunctionVirtualizationandSoftwareDefinedNetworksincarriergradenetworks.The Orchestratorplaysakeyroleinenablingperformance,scalability,availabilityandopenness. ItistheOrchestrator’sroleto mapnewservices’requestsontotheexistinginfrastructure inanautomatic,secureandefficientway,withouteverbeingabusinessoroperational bottleneck. T-NOVA’sorchestrator,namedTeNOR¹¹,isalignedwithETSIarchitecture requirements[ETSI,NetworkFunctionsVirtualisationV.,2014].Otheralternativeorchestra- torimplementationwereconsidered¹²,suchasOpenBaton¹³,OSM¹⁴andONAP¹⁵.

2.3.3.1 FunctionalOverview

DuetoitspivotalroleintheT-NOVAarchitecture,theOrchestratorimplementsappropriate interfacesto managetheinteractionwiththelayersaboveandbelowit.Specifically,the Orchestratorprovides:

1. ANorthboundinterfacetothe MarketplaceandtheNetworkFunctionStore;

2.ASouthboundinterfacetotheVIM.Thisinterfacesupportstheexchangeof metrics datageneratedbothattheinfrastructurelevelandattheVNF/NSlevel.Thesemetrics havetobecollected(andtransposed)andcommunicatedtotheOrchestratorinorder fortheOrchestratortoidentifyandinformtheVIMwhatactionsarerequiredtobe takensothattheNSSLAis maintained.

2.3.3.2 Architecture

TeNOR’s modulesarebrieflydescribedinthefollowing:

•NS/VNFManager:itisafacadeforthenorthboundinterface(the Marketplaceforthe NS Manager,theNS ManagerfortheVirtualNetworkFunction Manager(VNFM)), and managestheNS/VNFCatalog.Theproposedarchitectureembracesboththe conceptofgenericVNFMaswellasVNFspecificVNFMs,assuggestedbyETSI [ETSI,NetworkFunctionsVirtualisationV.,2014].

11https://github.com/T-NOVA/TeNOR

12AtthetimeT-NOVAprojectwasstarted,theseinitiativeswerenot matureenoughtobeintegrated.Asof writing,significantprogresshasbeen madeandforkinganexistingprojectwouldbeadvisable

13https://openbaton.github.io

14https://osm.etsi.org/

15https://www.onap.org/

14 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION

•Service Mapping:this modulecontainsthe mappingalgorithmimplementations, which maptherequiredresourcestosupportaNSinstancetothebestavailable locationintheinfrastructurerespectingtheconstraintsposedby:(i)thecurrent availabilityofnetworkinfrastructureresources,(ii)thetypeandamountofresources demandedbytheservicestobe mappedand(iii)SLAspecificneeds.SeveralService mappingalgorithmshavebeenproposedinT-NOVAbasedonIntegerLinearPro- gramming(ILP)formulationsandReinforcementlearning[Liberatietal.,2017].The approachadoptedto maximizetheinfrastructureproviderrevenueistryingembed as manyservice mappingrequestsaspossible.

•NS/VNFProvisioning:itacceptsrequestsforNSinstancesfromthe Marketplace (throughtheNS Manager)andforVNFinstancesfromtheVNFM;italso manages theNS/VNFInstancesrepositories

•NS/VNF Monitoring:itacceptsVirtual Machinebased monitoringdatafromthe lowerVIMlayerandmapsittothecorrespondingNS/VNFinstances.Thisdataislater giventothe Marketplace,forbothCustomersandFunctionProviderdashboards;

•SLAEnforcement:responsibleforcomparing monitoringdatatotheagreedSLAfor everyNSinstance,andgeneratesalertsforimpendingSLAbreaches.Dataassociated withapotentialbreachispassedtotheNS Manager,whichinitiatesthenecessary actionstoguaranteetheSLA(iteither migratesorscalesVNFinstancesorimproves theirnetworkconnections)

•ResourceRepository:providesinfrastructurerelatedinformationcollectedfromthe VIMandNFVIcomponentsoftheInfrastructureandVirtualization Management

•IVMLayer:TheIVMlayerintheT-NOVAsystemisresponsibleforprovidingthe executionenvironmentforVNFs.TheIVMiscomprisedofanumberofdomains includingtheNFVIandtheVIMand WICM.TheIVMprovidesfullabstractionofthe NFVIresourcestoVNFs.

•WICM:The WICMisresponsibleforprovidingthelinkbetween WideAreaNetwork (WAN)connectivityservicesandtheNFVIhostingVNFsincludingconnectivitytoNSs allocatedin morethanoneNFVI-POP.The WICMhasadedicatedTeNORinterfaceto receiverequestsforallocating WANconnectionstoservices.

2 .3 .4 Marketp laceLayer

T-NOVAintroducestheconceptofa MarketplaceinanNFVframework[Xilourisetal.,2014]. Theaimofthe MarketplaceistopromoteVNFserviceofferingsandfacilitatingcommercial activityandseamlessinteractionamongthevariousbusinessstake-holdersinteractingwith theT-NOVAsystem.

2.3. VNF-AS-A-SERVICE:THET-NOVAAPPROACH 15 2.3.4.1 FunctionalOverview

TheT-NOVA MarketplaceprovidesanintuitiveinterfacetotheunderlyingNFV MANOstack. Fourarethe mainfunctionalitiesidentified:

•PublicationofresourcesandNFadvertisement.Throughacustomerfront-end,Third- partyVNFdevelopersdescribetheirfunctionsintheT-NOVAFunctionStore,and customersplacetheirrequestsforservicesandvirtualappliances.

•VNFdiscovery,resourcetradingandservicematching.Throughabrokerage module customerscanplacetheirrequestsforT-NOVAservicesanddeclaretheirrequirements forthecorrespondingVNFs,receiveofferingsand maketheappropriateselections, takingintoaccounttheofferedSLAs[Markakisetal.,2016].Tradingandbillingpoli- ciessuchaslong-termlease,scheduledlease,short-termleaseorspot marketscanbe basedeitheronafixed-priceoraction-basedstrategies.

•Customer-side monitoringandconfigurationoftheofferedservicesandfunctions.Via aservicedashboarduserscaninteractwiththeT-NOVAOrchestratorplatformfor monitoringthestatusoftheestablishedservicesandassociatedNFs,aswellasfor performing —accordingtotheirassociatedpermissions — managementoperations onthem[Gardikisetal.,2016].

•Billingofservices.Thisincludestheestablishmentofpricing mechanismsfordif- ferentNFandthestudyofhowthesepricesareaffectedbySLAsevaluation,sothat customers mayreceivecertaincompensationsdependingontheoverallservicedeliv- ered[Skovieraetal.,2017].

2.3.4.2 Architecture

The Marketplaceiscomposedofvarious micro-services(seeFigure2.2)withthefollowing roles:

•TheBusinessServiceCatalogstoresalltheavailableserviceofferingsinthe market- place.

•TheBrokerageModulecomputesforagivenNetworkServiceSLA,eachtypeofVNF intheServiceFunctionsChain,whichVNFprovideroffersthe mostcost-effective alternative.

•TheDashboardprovidestheGraphicalUserInterfaceforallcustomer-facingservices. Itcanbeusedbyfunctionproviders,serviceprovidersandcustomers.

•TheSLA Management ModuleestablishesandstorestheSLAsamongalltheinvolved partiesandchecksiftheyhavebeenfulfilledornot.Itinformstheaccountingsystem forthepertinentbillableitems(penaltiesorrewarding).

16 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION

•TheAccounting Modulestoresalltheinformationneededforlaterbilling:usage resourcesforthedifferentservicesandSLAsevaluations

•TheBillingModuleproducesthebillsbasedontheinformationstoredintheaccount- ing module.

2 .3 .5 Summary

ThefunctionalspecificationsoftheOrchestratorandIVMaretightlyadaptedfromETSI requirements,andarecommontoallNFV MANO-compliantimplementationofNFV.As aconsequence,havingaVNFdeploysonT-NOVAassuresagoodportabilitytootherplat- forms.

Byintegratinganinnovative marketplacelayer,thebusinessaspectsaretakeninto account.SLAsallowhigh-levelnetworkservicestobedeployedontheplatformwiththe assurancethatthe mostcost-effectiveVNFsareselectedintheservicechainthanksto brokerage module.

Nowthatwehavepresentedthe mostsalientfeaturesofnetworksoftwarization,we discusstheopportunitiesinusingthemtosolveContentDistributionissuesintheoperator network.

2 .4 NetworkSoftwar izat ion ,anopportun ityforContent D istr ibut ioncha l lenges?

Inthissection,wepresentthecurrentstateoftheISPs market,andthechallengestheyhave beenconfrontedthroughouttheevolutionofcontentdistributionbusiness modelsand InternetAccesssincetheinceptionofcommercialInternetatthebeginningofthe1990s.

WeadvocatethatthenewtrendofNetworkSoftwarizationisthenexttechnological evolutionforFutureInternetthatwillhelpISPsstayingprofitableinanerawherethe commoditizationofIPaccessandOver-The-Top(OTT)contentdistributionisprevalent.

Forthis,wefirstgothroughalittlebitofhistoryandcomparetheevolvingrolesof ContentProvider(CP)andISPinthecontentdistributionvaluechain.Thenwedescribethe virtualizationtargetthatweanalyzedanddevelopedduringourresearchthatconstitutethe nextsteptowardavirtualizedcontentdistribution model. Wefinallypresentthechallenges oftheapproachesandthelessonslearnt.

2 .4 .1 ContentD istr ibut ionEvo lut ionsasaDr iversoftechno log ica l mutat ionsforInternetAccess

Inthissectionwedetailthe3 main mutationsofcontentdistributionstartingfromthe beginningofthecommercialInternetageinthe mid-1990tothenewdevelopmentsseen

2.4. NETWORKSOFTWARIZATION,ANOPPORTUNITYFORCONTENTDISTRIBUTION CHALLENGES?

2020

82%ofInternet userscanstream

HD

1990 2000 2010

Netflix 100M subscribers

*ITUv.34

33.6kbpsmodems *Home Gateway CPE Technologies

†Megaupload

*Google

*Napster *Youtube

*Netflix Streaming OTT Content

Distribution Services

*Netscape Navigator

Content Access Media *Flash Player

supports video *HTML5 standard

*HTML video

*Triple Play ISP Offerings *Commercial ISPs

with Internet

*OpenFlow *ETSI NFV Network Softwarization

Technologies

User-centric Networks and Services

4Gcommercial Deployment

Open Content Closed Gates

*vHG Specification

Ubiquitous HD content

*5G Commercial Deployment

*

{

17

Figure2.3:Cross-Chronologyoftechnological mutationsbetweenContentDistribution Services,andISPInternetaccessoffers

today. Weadvocatethatthewayusersaccesstheircontenton-lineisadriverforchange inthedesignandfeaturesforInternetaccesstechnologies. Weconcludebystatingthat thecurrenttrendofover-the-topcontentaccesscallsonce moreforinnovationintheISPs architectures.

ISPs

Content distribution near-monopoly

CPs ISPs

Challenging Legacy Content Distribution

Models

Content distribution near-monopoly

2.4.1.1 1990-2000Closedgatesera:ISP Webportalsanddial-upaccess

WhenInternetaccessstartedspreadinginhouseholdsinthe mid-1990,End-Users(EUs)werereceivingtheirInternetCon- nectionusingdial-up modems(v.34orv.90/92).Itwasnot uncommonforthemtohaveonlyalimitedaccesstotheopen Internet,throughServiceProviders WebportalssuchasAOL orCompuserve.Thosenowextinctwebportalswherepaidfor bytheInternetsubscriptionsandwereconsideredasafehavensincetheyonlyprovided accesstocontentscuratedbytheISPfortheEUsandlicensedtothemfromtraditional mediasuchasprintednewspapers,radioandtelevision. Whileservingcaptiveusersfrom theirwebportalsthroughtheirproprietaryclientsoftware(suchasCIMorAmericaOnline for Windows),ISPshadaverycomfortable marketpositioning.Thisshort-lived model wassoon madeobsoleteduetoEUsdemandingfasterconnectionspeedsthroughxDSL technologiesandtheriseofgratiscontentsaccessiblefromgratiswebbrowserswithfull HTMLstandardsupportsuchasNetscapeNavigator.

18 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION

CPs ISPs

Technological competition for added-value content

distribution New Business models

adoption

2.4.1.2 2000-2010OpenContentera:GratisContentsandBroadbandaccess

AttheturnoftheXXthcentury,EUsstartedaskingforservices thatwerenotprovidedthroughportalsbutinstead madedi- rectlyaccessibleontheopenInternet.InternetStartupssuch asGoogleandFacebookinventednewbusiness modelsfor contentsandservices,relyingonsmartcontent monetization throughadvertising,usertargetingoraffiliation[Evans,2009]. Userswereseducedbythepromisesofgratiscontents,anddevelopedahugeappetite forinteractiveand multimediacontents,drivingupdemandforbroadbandInternet.The AdobeFlashPlayerhasbeenakeyenablerthatalloweduserstoaccess multimediacontent regardlessoftheirOSorbrowseranddemocratizedvideostreamingsince2002.

Thisnewcontentdiffusionparadigmwasspeciallydisruptivefortraditionalwritten news media[Saba,2009],whichfacedasharpdeclineduetotheadvertisingrevenues mov- ingawayfromphysical mediumtoitson-linecounterpart.TVandfilmindustryquickly adaptedtothisnewerabyproposingVideoonDemandserviceswithinitiallyonlylimited success,fortworeasons.Theseserviceswerecompetingagainstotherformofgratiscon- tentdistributionsuchasillegalpeer-to-peerfilesharing(suchasNapster,whichallowed userstosharefilesbetweenthemwithoutrequiringacentralservertohostthefiles),ille- galon-linehostingservices(suchas Megaupload,whichalloweduserstostreamvideos withouthavingtodownloaditinthefirstplace).Anotherfactorthattemporarilyhindered theshifttowardspayingcontentsisqualityofexperience. Thebroadbandpenetration wasnotsufficienttoreachacriticalcustomer mass,andthelimitedavailabilityofdown- streambandwidthandlackofpropercontentdeliverynetworks,imposedsubparqualityof experiencewrt.premiumTVsubscriptionsthroughIP/TV(offeredthroughdedicatedSet- top-boxes),proposedbyISPsintheirnewtriple-playoffersincludingInternet,telephone andTVaccess[Kellyetal.,2012].

ToproposethesenewbundlesandadapttoEUsrequirements,ServiceProvidershad toinnovateandreplacetheirbroadband modemsby morecomplexappliancestobecome properHomeGateways[Holliday,1997].Thesealways-ondevicesaredesignedtobereliable, remotely manageableandaffordable.Theyarealsoextensibleinthesensethattheycan supportnewphysicalperipheralsandnetworks,aswellasnewservicesforsecurityandmul- timedia[DenHartogetal.,2004].Standardizationbodiesalsostartedissuingspecifications forthosecomplexdevices[BroadbandForum,2005],[BroadbandForum,2006].

Thiseracametoanendduetotheconjunctionoftwodifferentphenomenon:high- speedfixedand mobileInternetdemocratizationandthefightagainstpiracy.

Theyears2010witnessedadramaticincreaseinavailablebandwidthworldwide.In 2008Globallyonly20%ofusershada+5MbpsAveragePeakConnectionSpeed(witha mere26%intheUS)[AkamaiTechnologies,2008].In2017however,thisratiohasrisen to82%globally(andvirtuallyeverywhereintheUS,wherehalfofthepopulationcan downloadat+15Mbps)[AkamaiTechnologies,2017]. Mobileaccessalsoimprovedby1

2.4. NETWORKSOFTWARIZATION,ANOPPORTUNITYFORCONTENTDISTRIBUTION

CHALLENGES? 19

orderof magnitude,providingonaverage10MbpsintheUSandoften much morein Europe[SANDVINE,2016]. Withjust5Mbpsbandwidthavailable,userscanenjoyreal-time videostreamingwithqualitiesrangingfromstandard480presolutiontoHD720p¹⁶,without theburdenofwaitingthedownloadtocomplete,likeintraditionalpeer-to-peerfilesharing services.

Thisconveniencewasnottheonlyreasonwhypeer-to-peerhavelost momentum. Followingunprecedentedlobbying[Hugenholtzetal.,2000]fromContentOwnerstopro- tecttheircopyrights,legislatorsrespondedthroughtheadoptionofthe WIPOCopyright Treaty[Ficsor,2001]becomingeffectivein2002,followedbyitsimplementationsinnational orsupranationallegislation,suchastheDigital MillenniumCopyrightAct[LunneyJr,2001]

intheUSandtheCopyrightDirective(Directive2001/29/EC)inEurope[Westkamp,2007]. AsPiratewebsiteswereshutdown,usersturnedtheirbacktopeer-to-peerfilesharing(from 60%ofInternetbandwidthin2006[Ferguson,2006]downto3%today[SANDVINE,2016]) toadoptgratisorpayingOver-the-topprovidersastheir mainsourceofon-lineentertain- ment.

2.4.1.3 2010+UbiquitousStreamingera: Multichanneldistributionand Commoditizedubiquitousaccess

Figure 2.4: Peak Period Traffic Composition - North America, Fixed Ac- cess[SANDVINE,2016]

CPs

Content distribution near-monopoly

CPs ISPs

Commoditization Mature OTT

Business Models

Today,Over-the-topcontentdistribution,andespecially videocontent,hasbecomeprevalent.Combinedwith music streaming,itreaches71%ofPeakPeriodDownstreamTrafficin NorthAmericaasshownonFigure2.4.Totargetamainstream

16Googlerecommendedbitratehttps://support.google.com/youtube/answer/1722171?hl=en

20 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION market,OTTCPsadaptedtoEUsdemandsofseamlessand ubiquitousaccesstostreamingcontentbyrollingoutplethora ofdifferentcontentaccesstechnologies:

•dedicatedwebsitesaccessiblethroughwebbrowsers¹⁷,¹⁸.

•thirdpartyapplicationsdownloadedoncustomerssmartdevicessuchassmart- phones,tablets¹⁹,smartTVs[Leeetal.,2013],orgamingconsole²⁰

•Customer-purchasedconnectedDigital MediaPlayers(e.g.AppleTV,AmazonFireTV, GoogleChromecast)

Withthisvastchoiceoftechnology,EUcanenjoytheirOTTcontentwherevertheyhave anIPconnectivity.AsISPbecomes moreorlessinterchangeableandcanonlycompete onprices,Internetconnectivityisacommoditized market[Feamsteretal.,2007]. Asa result,Internetbroadbandaccesspricesaredecreasingovertheyears.Forexample,from February2012toautumn2015,pricesforbroadbandintheEU28havefallenby7.7%

to25.9%thisdecreaseaffectsalltypesofserviceofferingsandallspeedbasketacross Europe[EuropeanCommission,2016].

Inthiscontext,ISPsfacethreechallengespresentedinTable2.1,forwhichwepropose solutionsdetailedinthenextsection.

2 .4 .2 NetworkSoftwar izat ion ,anopportun ityforcontentde l ivery?

Fullyawareoftheirdifficultposition,ISPsstartedembracingNetworkSoftwarization,if notbydeployingitintotheirnetwork,thenatleastbyheavilyinvestinginitsunderlying technologies(NFV,SDN,Orchestration,Cloudplatforms).OntopofthetraditionalStan- dardizationBodiesandIndustryconsortiawhichareconsideringthedifferentchallenges inherenttoNetworkSoftwarization(e.g.IETFRFC7665forServiceFunctionchaining), Telcosarealsocontributingtothegovernanceandworkforceofopen-sourceprojectsused asNFVandSDNbuildingblocksaswereportedinTable2.3. Whatthistrendisrevealing,is thatNetworkSoftwarizationisthenexttechnologicalevolutionchosenbytheISPsinorder toaddressChallenge(1).

Inthisthesis,wedecidedtofocusonspecificissuesrelatedtotheevolutionofcontent distributiontothedawnofnetworksoftwarization.Forthisreason,wepresentasolution basedonNetworkSoftwarizationthataddresschallenges(2)and(3)throughthedeployment

17https://www.netflix.com/

18https://www.primevideo.com/

192011 https://media.netflix.com/en/press-releases/netflix-expands-support-for-android-powered- smartphones-and-tablets-migration-1

20https://media.netflix.com/en/press-releases/coming-soon-netflix-members-can-instantly-watch- movies-and-tv-episodes-streamed-to-tvs-via-the-playstation-computer-entertainment-system-migration- 1

2.4. NETWORKSOFTWARIZATION,ANOPPORTUNITYFORCONTENTDISTRIBUTION

CHALLENGES? 21

ofaVirtualContentDeliveryNetworkasVirtualNetworkFunctionsoldthroughaVNF-as- a-serviceplatform.

Tofurtherclarifywhataretheprosandconsofproposals(2)and(3),weconducteda SWOTanalysiswhereweanalyzedtheirstrengths,weaknesses,opportunities,andthreats. Table2.2summarizethe mainideas.

Strengths:ISPshaveinvestedalottobuildtheirrobusthigh-speedphysicalinfrastruc- turesfromIP-backboneto metronetworktothelast milesegment.Theseinfrastructures canbeleveragedtoproposenewservicesatscale.AsEUsexpectationsintermqualityof experienceareveryhigh,proposingaguaranteedbandwidthanddelayisakeystrength. ISPsaretodaytheonlyactorcapableof managingthenetworkend-to-end,henceproviding guarantiesfromthecontentserverdowntotheuserpremises.

Weaknesses:NetworkSoftwarization mayrequiredeployingnewcompatiblehardware (forwardingdevicessupportingprogrammability,NetworkFunctionVirtualizationInfras- tructurePointsofPresence).It maybehardforISPstoinvestinnewtechnologiesbefore existingonesreachtheirend-of-lifeinacommoditized marketwheretheprofit marginsare thin.Anotheraspectthat mayimpedetheadoptionofNetworkSoftwarizationisthatextra effortisneededtoadapttheinternalorganizationofISPstoacceptandbenefitfromthe technologies[Viginier,2017][CantóPalancaretal.,2015].

Opportunities:SeveralopportunitiescanbeexpectedbyadoptingNetworkSoftwariza- tion.First,runningnetworkfunctionsassoftwarecanlowerbothCAPEX(capitalexpendi- ture)andOPEX(operationalexpenditure)especiallyinDeployment(Roll-out)andUpgrade, Capacity Management,TransportNetworkOperations,ServiceAssuranceandEnvironmen- talCosts[Hernandez-Valenciaetal.,2015].AnotherbenefitfromNetworkSoftwarization isthereducedtime-to-marketneededinordertoroll-outnewservices[Hanetal.,2015]. Bydesign,deployingVirtualNetworkFunctionsonlyinvolvesimplementingfeaturesas

Table2.1: MainchallengesfacedbyISPandproposedsolutionsdevelopedinthisthesis ChallengesDescriptions Proposals

Challenge1 Reducetheircoststostaycompeti-

tiveinacommoditized Market AdoptNetworkSoftwarizationby implementingNFV-capablePoint- of-presences(POPs)anddeploy VNFs(Chapter3)

Challenge2 BenefitfromtheOTTcontentde-

liverytrend Establish a collaboration with otheractorsofthecontentdelivery valuechain(Chapter4)

Challenge3 Increasetheirportfoliotosellnew

added-valueservices Marketaddedvalueservicesbased ontheirinfrastructure(Chapters5)

22 CHAPTER2.PERSPECTIVESINNETWORKSOFTWARIZATIONANDCONTENT DISTRIBUTION Table2.2:SWOTAnalysisofadoptingtheproposals(1),(2)and(3)ofTable2.1

Helpful Harmful

Internal

Strengths

End-to-endnetwork management Existinginfrastructure

Weaknesses NewcorporateOrganization InvestmentsinaCommoditized Market

TechnicalDebt(legacyhardware)

External

Opportunities LowerCAPEXandOPEX Repurposablevirtualresources

VirtualCDN

Threats

DeploymentchallengeinISPNetworks Mustdesigncollaboration modelswith CP

software,relegatingthehardwaredesigntocommodityservervendorsandleveraging open-sourcesolutiontoimplementthevirtualinfrastructure.Thankstothesupportof multi-tenancybySDNcontrollers[Muñozetal.,2015],sellingconnectivityasaserviceis feasible[Feamsteretal.,2007],[Manthenaetal.,2015],[Aflatoonianetal.,2015].Conse- quently,ISPscancreatenewbusinessopportunitiesbyimplementingvirtualoverlayson topoftheirnetworkoreasilyslicingthemtosellpremiumnetworkconnectivitytothird parties.Finally,NetworkSoftwarizationcanbeusedtoroll-outnewaccessarchitectures thatsupportsthefastdeploymentofnewservicesforcontentdelivery(e.g.VirtualContent DeliveryNetworks,seesection3.2).DeployedcomputingresourcessupportingNetwork Softwarizationcanbeeasilyre-purposedtosupportnewservices.

Threats: Eveniftheperceivedbenefitsareclearand migratingtoafullypro- grammablenetworkfabrichasprovenfeasibleandbeneficialforDataCenterOperators [Singhetal.,2015],itremainsanopenresearchtopicforISPsnetworks.Indeed,deploying softwarizedISPsnetworkshavesomepracticalimplicationssuchascurrentlegacyhardware deploymentupgrade[Poularakisetal.,2017],trafficheterogeneity,numberofflows.It may bealsoproblematicto maintainaglobalviewofnetworksofsuchscalegiventhecurrent architectureofcontrolsoftware[Rodriguez-Nataletal.,2017].Fromabusinessperspective, ISPsneedtoassurethattheycanofferusefulserviceforCPs. Designingacollaboration modelbetweenISPandCPleveragingontheexistingStrengthsofISPs mayprovedifficult (seesection4.2.2).

2 .5 Conc lus ion

InthisChapter,wehaveprovidedanoverviewofnetworksoftwarizationtechnologiesand thepossibleopportunitiestheypresenttoaddresscontentdistributionchallengeinthe operatornetwork. WebelievetheseemergingparadigmsareanopportunitytoputtheISPs backinthegamethroughcostreductionandnewrevenuestreamthroughthedeployment ofnovelcontentdeliverysolutionsbasedonNFV.Tosupportthisideawedescribea model ofaContentDeliveryNetworkimplementedasaVNFinthenextchapter.