Introducing ONOS - a SDN network operating system for Service Providers

Transcription

1 WHITEPAPER! Software Defined Networking (SDN) Introducing ONOS - a SDN network operating system for Service Providers! ThiswhitepaperdescribesONOS,aSDNnetworkoperatingsystemdesignedforhigh availability,performance,scale=outandrichabstractions.

2 SUMMARY The Open Network Operating System (ONOS) is the first open source SDN network operating systemtargetedspecificallyattheserviceproviderandmissioncriticalnetworks.onosispurpose builttoprovidethehighavailability(ha),scale=out,andperformancethesenetworksdemand.in addition,onoshascreatedusefulnorthboundabstractionsandapistoenableeasierapplication developmentandsouthboundabstractionsandinterfacestoallowforcontrolofopenflow=ready andlegacydevices.thus,onoswill bringcarriergradefeatures(scale,availability,andperformance)tothesdncontrolplane enablewebstyleagility helpserviceprovidersmigratetheirexistingnetworkstowhiteboxes lowerserviceprovidercapexandopex ONOShasbeendevelopedinconcertwithleadingserviceproviders(AT&T,NTTCommunications), with demanding network vendors (Ciena, Ericsson, Fujitsu, Huawei, Intel, NEC), R&E network operators(internet2,cnit,create=net),collaborators(sri,infoblox),andwithonftovalidateits architecturethroughrealworldusecases. THESERVICEPROVIDERNEED! Theproliferationofmobiledevices,OTTservicesanddistributionofcontentacrossthecloudhave pushedserviceprovidernetworkstoapointwheretheyareinurgentneedofreinvention.service Providerswanttomaketheirnetworksagileandefficientinordertomeetthechallengesofthese exponential bandwidthdemands andwantto beabletocreaterevenue streamswith innovative servicesandnewbusinessmodels. SDNANDONOSTOTHERESCUE! Injustashorttime,SoftwareDefinedNetworking(SDN)hasbecomethetechnologyofchoicefor enablingmobility,virtualization,andthecloud.storageandcomputehavebeenvirtualizedfor years,yetonecouldnotcapturethefullvalueoftheseadvancementsbecausethenetworkiswhat enablesthevaluetobeunlocked=itisthefabricthatconnectsthemtogetherandtoapplications. ThekeySDNconceptthatenablessimilarnetworkinnovationistheseparationofthecontrolplane fromthedataplaneinverticallyintegratednetworkdevices.anon=proprietaryprotocolsuchas OpenFlowallowsthecontrolplanetoprogramthedataplaneinamuchmoreopenandefficient way.inaddition,thisseparationallowsnetworkhardwareandsoftwaretoevolveindependently andfacilitatesthereplacementofexpensive,proprietaryhardwareandfirmwarewithcommodity hardwareandopensourcesoftware.havinganoperatingsystemthatmanagesnetworkresources andprovidestheabstractionsandapisformanaging,monitoring,andprogrammingnetwork devicesgreatlysimplifiesthecreationofinnovativeandbeneficialnetworkapplicationsand servicesthatoperateacrossawiderangeofhardware.opennetworkoperatingsystem(onos) wascreatedtobethisoperatingsystemandhasthefollowinggoals: Liberatenetworkapplicationdevelopersfromknowingtheintricaciesofproprietary hardware. Allownetworkoperatorstobreakfreefromtheoperationalcomplexitiesofproprietary interfacesandprotocols. Re=enableinnovationtohappenforbothnetworkhardwareandsoftware,independently,! ontheirowntimescales. 2!

3 WHYANETWORKOPERATINGSYSTEM? Therearemany opensource SDNcontrollers;itis therefore reasonabletoask Why ONOS, and whyanetworkos?.collaboratorsatstanford,berkeley,andniciranetworksdevelopedseveral opensourcecontrollersduringthepastsevenyears,includingnox,beacon,snacandpox.these controllers were designed to explore and demonstrate SDN potential. Much was learned from workingwiththesecontrollersandbybuildingtheapplicationsanddemonstrationstheyenabled. However,itisimportanttounderstandthesecontrollerswerenotdesignedtobeafoundationfor commercial products. They don t have the key features such as scalability, high availability, and performance.moreover,theyhaveprimitiveprogramminganddevice=orientedabstractions. These controllers fundamentally relayed OpenFlow messages directly to applications, and applications directly created OpenFlow messages for the network devices. In this way, these controllers are more like device drivers. They are not designed to have the critical scalability, availability and performance features of a complete SDN control platform. What is needed is a networkos ONOShasbeencreatedtofulfillthisneed. Recallthatanoperatingsystemisresponsibleforthefollowingfunctions: Itmanagesfiniteresourcesonbehalfofresourceconsumers.Indoingso,itensuresthatall consumershaveappropriateaccess=noneisstarved,allarehandledfairly. ItisolatesandprotectsNOSusersfromeachother=eachuserappearstohaveaccesstoa full setofresources.itmultiplexesbetween multipleapplications andmultipledevices.it may also virtualize some or all of the resources to allow consumers their own virtual instantiationoftheos. It provides useful abstractions to enable users to more easily consume services and resources managed by the operating system, without having to understand all of the complexity. It provides mechanisms for different devices to be easily added to and controlledbytheoperatingsystemwithoutrequiringtheapplicationtochange. Itprovidessecurityfromtheexternalworldtotheusersoftheoperatingsystem. It supplies useful services so that users of the operating system don t have to build and rebuildthesameservices. Theseareexactlythethingsneededbyapplicationsrunningonanetwork.Acontrolleristypically too limited in scope = it sets out to control a device. It does not necessarily provide useful abstractions;itdoesnotnecessarilyprotectdifferentcontrollerusersfromeachother;itdoesnot provideadditionalusefulservices.onossetsouttoprovideallofthefunctionalityofanoperating system=notjustthefunctionalityofacontroller.howdoesonosaccomplishthis?byarchitecting thesoftwarewithserviceproviderfeatures. ONOSARCHITECTURE ONOShasbeenarchitectedfromthebeginningwiththeserviceproviderinmind.HighAvailability, Scale=out,andPerformancearefundamental,asarepowerfulabstractionsattheNorthboundand Southboundinterfaces.! 3!

4 ThefollowingarethedefiningfeaturesofONOS: Distributed!Corethatprovidesscalability,highavailability,andperformance!bring carriergradefeaturestothesdncontrolplane.theabilityofonostorunasaclusteris onewaythatonosbringswebstyleagilitytothesdncontrolplaneandtoservice providernetworks. Northbound!abstraction/APIsthatincludenetworkgraphandapplicationintentstoease developmentofcontrol,management,andconfigurationservices.thisabstractionis anothergoodexampleofhowonosbringswebstyleagilitytothesdncontrolplaneand toserviceprovidernetworks. Southbound!abstraction/APIsthatenablepluggablesouthboundprotocolsfor controllingbothopenflowandlegacydevices.thesouthboundabstractioninsulatesthe coreofonosfromthedetailsofdifferentdevicesandprotocols.thesouthboundisakey enablerformigrationfromlegacydevicestoopenflow=basedwhiteboxes. Software!Modularitymakesiteasytodevelop,debug,maintain,andupgradeONOSasa softwaresystembyacommunityofdevelopersandbytheproviders. Eachofthesearchitecturalfeaturesisdescribedinmoredetailinthefollowingsections. DISTRIBUTEDCORE! ONOSisdeployedasaserviceonaclusterofservers,andthesameONOSsoftwarerunsoneach server.deploymentsymmetryisanimportantdesignconsiderationasitenablesrapidfailoverin theeventofanonosserverfailure.thenetworkoperatorcanaddserversincrementally, withoutdisruption,asneededforadditionalcontrolplanecapacity.theonosinstanceswork togethertocreatewhatappearstotherestofthenetworkandapplicationsasasingleplatform. Applicationsandnetworkdevicesdonothavetoknowiftheyareworkingwithasingleinstance orwithmultipleinstancesofonos.thisfeaturemakesonosscalable onecanscaleonos capacityseamlessly.itisthedistributedcorethatdoestheheavyliftingtorealizethese capabilities. Figure!1.!Distributed!Core!! 4!

5 Thedistributedcoreprovidesmessaging,statemanagementandleaderelectionservicestoand betweeninstances.asaresult,multipleinstancesbehaveasasinglelogicalentity.usinghigh speedmessaginginapublish/subscribemodel,instancescanquicklyinformotherinstancesof updates.builtintoonosarerecoveryprotocolsfordealingwithupdatesthatarelostdueto instancefailures.avarietyofoperationalstateismanagedbetweeninstancesusingseveral mechanisms=eachbeingappropriateforthetypeofstate.threeexamplesincludetheapplication intents,thetopologydatabase,andtheflowtables=eachhasuniquesize,read/writepattern,and durabilityrequirements.aleaderelectionserviceensuresthatswitcheshaveoneandonlyone masterinstance.together,themessaging,statemanagement,andleaderelectionmechanisms enablehighthroughput,lowlatency,andhighavailabilityofthecluster. Whatdoesthismean?Fordevices,theywillalwayshaveasinglemasterandifthemastergoes down,theywillbeabletoconnecttoanotherinstancewithouthavingtorecreateand resynchronizetheflowtables.forapplications,theycancountonhavingaconsistentviewofthe networkthroughthenetworkgraphabstraction.inaddition,afailureofaninstanceorafailurein thedataplaneistransparenttotheapplication.thesebothgreatlysimplifyapplication developmentanderrorhandling. Fromabusinessperspective,itbringsaveryhighlyavailableenvironmentsothatapplications donotexperiencenetwork=relateddowntime.italsomeansthattheserviceprovidercaneasily addcontrolplanecapacityasthenetworkgrows,withoutdisruptiontothenetwork.through thesamemechanism,thenetworkoperatoralsohasthecapabilitytoupdatesoftwarewith zerosystemdowntimebytakinganinstanceoffline,upgradingit,andbringingitbackonline. Insummary,thedistributedcoreisthekeyarchitecturalfeatureofONOSthatbringscarrier gradefeaturestothesdncontrolplane. NORTHBOUNDABSTRACTIONS! TherearetwopowerfulNorthboundabstractions:theIntentFrameworkandtheGlobal NetworkView. TheIntentFrameworkallowsanapplicationtorequestaservicefromthenetworkwithout havingtoknowdetailsofhowtheservicewillbeperformed.thisallowsnetworkoperatorsas wellasapplicationdeveloperstoprogramthenetworkatahighlevel;theycansimplyspecify theirintent:apolicystatementorconnectivityrequirement. Someexampleintents: SetupaconnectionbetweenHostAandHostB SetupanOpticalPathfromSwitchXtoSwitchYwithZamountofbandwidth Don tallowhostatotalktohostb! 5!

6 Figure!2.!Intent!Framework! TheIntentFrameworktakessuchrequestsfromallapplications,figuresoutwhichonescan andcannotbeaccommodated,resolvesconflictsbetweenapplications,appliespoliciessetby anadministrator,programsthenetworktoprovidetherequestedfunctionality,anddelivers therequestedservicestotheapplication. Anintentistranslatedintomultipleobjectives=forexample,anintenttohaveaconnection betweentwohoststranslatesintotwoobjectives,eachprovidingonedirectionofflow.the objectivesarecompiledintoinstructionsthataresenttothenetworkdevices.thisprocessis doneunderthecontrolofpoliciesspecifiedbythenetworkoperatorandinawaythatresolves conflictsbetweendifferentintents. TheGlobalNetworkViewprovidestheapplicationwithaviewoftheNetwork=thehosts, switches,links,andanyotherstateassociatedwiththenetworksuchasutilization.an applicationcanprogramthisnetworkviewthroughapis.oneapiletsanapplicationlookat theviewasanetworkgraph.someexamplesofwhatcanbedonewiththenetworkgraph include: createasimpleapplicationtocalculateshortestpathssincetheapplicationalreadyhas agraphicalviewofthenetwork maximizenetworkutilizationbymonitoringthenetworkviewandprogramming changestopathstoadjustload(trafficengineering) steertrafficawayfromapartofthenetworkthatisbeingupgradedorthatisbeing quarantinedforavirus. Technically,thenorthboundabstractionsandAPIsinsulateapplicationsfromdetailsofthe networkthatarenotneededbytheapplication.theabstractionscanalsoinsulateapplications fromnetworkevents(likelinkdown)whendesiredbytheapplication.conversely,itinsulates! 6!

7 ! 7! theoperatingsystemfromtheapplicationsallowingtheoperatingsystemtodoitsjobof managingrequestsfrommultiple,competingapplications.fromabusinessperspective,this increasesapplicationdevelopmentvelocityandallowsnetworkchangeswithoutapplication downtime. SOUTHBOUNDABSTRACTIONS! Thesouthboundabstractionisbuiltusingnetworkelements,suchasswitches,hosts,orlinks.The southboundabstractionofonosrepresentseachnetworkelementasanobjectinageneric form.throughthisabstraction,thedistributedcorecanmaintainthestateofthenetwork elementwithouthavingtoknowthespecificsoftheelementrepresentedbytheunderlying driver.ineffect,itallowsthecoretobesouthboundprotocolanddeviceagnostic.thenetwork elementabstractionisalsowhatallowsadditionofnewdevicesandprotocols.onosandits southboundabstractionallowplug=insforvarioussouthboundprotocolsanddevices,wherea plug=inmapsortranslatesgenericnetworkelementdescriptionoroperationonthedevicetothe specificandvice=versa.thusthesouthboundenablesonostocontrolormanagemultiplediverse devices,eveniftheyusedifferentprotocols(openflow,netconf,etc.). Architecturally,thesouthboundiscomposedofthelayersshowninfigure3.Atthebottomare thenetworkdevicesorelements.onosinteractswithdevicesthroughprotocols.theprotocol specificsareabstractedawaybythenetworkelementplug=inoradapter.asaresult,thecoreof thesouthboundcanmaintainitsnetworkelementobjects(devices,hosts,links)withouthavingto knowthespecificsoftheprotocolsandnetworkelements.throughtheadapterapi,the distributedcoreiskeptuptodateonthestatusofthenetworkelementobjects.theadapterapi insulatesthedistributedcorefromhavingtoknowdetailsaboutprotocolsandnetworkelements. Themainbenefitsofthesouthboundabstractionsinclude: abilitytomanagedifferentdevicesusingdifferentprotocols=withouteffectonthe distributedcoreofthesystem abilitytoaddnewdevicesandprotocolstothesystem easeofmigrationfromlegacydevicesandprotocolstowhiteboxessupportingopenflow SOFTWAREMODULARITY! Softwareconstructionmatters.Donecorrectly,softwareiseasytoenhance,change,and maintain.theonosteamhasputgreatcareintomodularitytomakeiteasyfordevelopersto workwiththesoftware. Whatismodularity?Itishowthesoftwareisstructuredintocomponentsandhowthose componentsrelatetooneanother.asapparentfromdiagrambelow,themajorstructuresof ONOSareitstierscenteredaroundthedistributedcore.Thus,atthemacroleveltheNorthbound andsouthboundapisprovideaninitialbasisforinsulatingapplications,coreandadaptersfrom eachother.newapplicationsornewprotocoladapterscanbeaddedasneededwithouteach needingtoknowabouttheother.

8 Figure!3.!ONOS!Layers! Similarly,beneaththismacroleveldepictionaresmallersubstructureswithintheCoreitself, whichexisttolimitthesizeofanyparticularsubsystemandtofacilitatemodularextensibility. Again,theserelyheavilyoninterfacestoserveascontractsforinteractionsbetweendifferent partsofthecore,allowingeachpartofthecoretoevolveindependentlyfromothers.this enablesnewalgorithmsormoreefficientdatastructurescanbeprovidedovertime,without affectinglargepartsofthesystemortheapplications. Clearly,majorfocushasbeenplacedonmakingsuretheinterfacesencourageseparationof concernsandresponsibilitiesinordertokeeptheinteractionsbetweensubsystemsasnatural andsimpleaspossible.thisisessentialforstableevolutionofthesoftwarebase.forexample, onthesouthboundapi,carewastakentoraisethelevelofabstractioninordertoavoid generalbiastowardsanyspecificprotocolandalsotoenforcetheconventionwherethecore, andnottheadapterscreatethenetworkmodelobjects. ONOSsourcetreestructureissetuptonotonlyfollow,buttoenforcethesearchitectural principles.modulesarekeptreasonablysmallanddependenciesamongthemformanacyclic graph,wheredirectdependenciesbetweenmodulesarerealizedthroughapimodulesas depictedindiagrambelow. Figure!4.!ONOS!Modules!! 8!

9 Insummary,therearemanybenefitstosoftwaremodularity: Architecturalintegrityandcoherence Simplifiedteststructure,allowingmorecomprehensivetesting Easiermaintenancewithfewersideeffectsofchanges Extensibilityandcustomizationofcomponents Avoidanceofcyclicdependencies ONOSVALUEPROPOSITION=ENABLINGOPERATORUSECASES! Multi=layerSDNcontrolofpacket=opticalcore! ServiceProvidersoperatemulti=layernetworks.Forexample,aserviceprovideroperatesIP packetnetworkaswellasatransportoropticalnetwork.atunnelinglayermayalsoexistontop oftheipsubstratetocreateservicessuchasvirtualiplayernetworks.eachoftheselayersis managedindependentlytodayresultinginlowlevelsofnetworkutilization,highoperational costs,andreconfigurationcyclesthatareinmonthsratherthanminutes.forexample,intoday s environment,packetnetworkdesignersprovisionadditionalcapacitytohandlenetworkfailures andpeakburstytrafficloadsaswellasfailures;andindependently,transportnetworksdesigners dothesameattheopticallevel.moreover,packetnetworkdesignersliketooperateat30 averageutilization.this,inaggregate,leadsto4=5xtotalover=provisioningofcapacity. SDNcontrolofmulti=layernetworksaddressestheproblemsmentionedabove.Thesolution includesthreecomponents:(1)additionofopenflowlikeprogrammabilitytoopticaltransport elementssuchasroadms;(2)onostobuildanetworkgraphviewforeachlayerofthenetwork andmaintainthemappingorcorrespondenceamongthem;and(3)developmentofapce applicationononosthatsetupsandtearsdownpath,takingintoaccountmultiplecorrelated networkgraphs. ONOSPCEapplicationisabletoconfigure,monitorandorchestratethelayersasthoughitwerea singleentity.forexample,ipconnectionchangescantriggerautomaticprovisioningofoptical paths.theoperatornowhastheabilitytoloweroperationalcoststhroughcentralcontrol,to raisenetworkutilizationonalllayers,andtoreconfigurethenetworkinminutes.oneofthefirst applicationsofthiscapabilityisabandwidthcalendaringapplicationthatallowsbandwidthtobe reservedinthefuture.onosprovisionsthepacketandopticallayerstoprovidethebandwidth, andthenmonitorstheresourcestoperformre=routingandadjustmentsbasedonrealtime networkeventsandotherchanges. Figure!5!.!MultiNlayer!SDN!control!! SDNcontrolofmulti=layernetworksisanexcellentexampleofhowSDNcontrolimplemented! withonoscanleadtosignificantsavingsincapexandopexaswellasenablenewclassof 9! services.

10 SDN=IPPeeringandScalingSDNControlPlane! Today,AutonomousSystems(AS)connecttotheInternetandwitheachotherusingBGPto shareroutinginformation.thesdn=ippeeringapplicationononosisdesignedtohelpservice providersstartsmallandgrowtheirsdndeployments.aserviceprovidercandeployasmall SDNnetworkoranSDNislandasanASandusetheSDN=IPpeeringapplicationtoseamlessly connectthesdnnetworktotherestoftheinternetusingbgp.withthesdn=ipapplication,an SDNnetworkappearsasjustanotherAStotherestoftheInternet.Overtime,theservice providercankeepingscalingthesdnnetworkandrealizeallthebenefitswithoutimpactingits peeringwiththeinternet.moreover,aserviceprovidercanusethesdn=ippeeringapplication tointer=connectmultiplesdnnetworkstocreatealargesdnautonomoussystem(as)that peerswiththeinternetthesamewayasotheras. TheSDN=IPapplicationpeerswithASborderroutersandexchangesrouteinformationforIP prefixesasisdonebetweenstandardastoday.thesdn=ippeeringapplicationusestherouting informationtosetupforwardingpathsforvariousinternetprefixesonthesdnnetwork.thus SDNnetworkcanactasatransitnetworkforsomeprefixesandcanforwardIPtraffictoand fromanyipaddressthatisreachable. Inaddition,SDN=IPapplicationcanbeusedtoscaleONOS=basedSDNcontrolplane.Forexample SDNnetworksordomainscanbeinterconnectedthroughBGPsimilartonon=SDNAStoday. Confederationworksinasimilarwayaswell=agroupofSDNdomainscanbeviewedbytherest oftheinternetasasingleas. Figure!6.!SDNNIP! ThusSDN=IPpeeringapplicationplaysanimportantroleinincrementalandseamlessSDN deploymentinaserviceproviderinfrastructure.on.labisdeployingsdn=ippeeringapplication oninternet2,anditisbeingusedtointerconnectcampusnetworksthataremigratingtosdn viainternet2 ssdnbackbone.!! 10!

11 NetworkFunctionsasaService(NFaaS)inCentralOffice! Telecomprovidershaveavaluableassetintheirnetworkstoday=thecentraloffices.These centralofficesaregeographicallyclosetoalargenumberofendusers,andthustheyarestrategic inthattheyenablethetelecomproviderstoofferservicesatscaletoalargenumberof customerswithperformanceandpredictability.forexample,at&toperatescloseto4,500 centralofficesinthecountryandatypicalcentralofficeinalargemetroareacanserveasmany as~100kwiredand~100kcellularsubscribers,and100sofenterprises.atypicalcentraloffice haslotofaccessandswitchingcapacityandmanypurposebuiltmiddleboxesforvariousnetwork functions.thoughcentralofficesarestrategictotelecomoperators,theyhaveevolvedover manydecadesandhavesignificantcomplexityintermsofnetworkswitching/routing,middle boxes,andterminationofcustomers.theyrepresentsignificantcapexandopexfortheservice providers. Notsurprisingly,serviceproviderswanttore=architectthecentraloffice.Theywanttobringthe datacentereconomiesandagilitytothecentraloffice.thismeansbuildingthecentraloffice networkfabricusingsdn,transformingnetworkfunctionsimplementedusingpurposebuilt middleboxestosoftwarerunningonx86servers(socallednfv),andanorchestrationsystem thatcanorchestratenetworkfunctionsandnetworkflowsforasubscriberorenterprise customer==dynamicallytoserveindividualcustomerswhilerealizingvarious policies of both the customer and the provider. Figure!7.!NFaaS!in!Central!Office! Thistransformationofthecentralofficewillallowtheserviceproviderstoquicklycreate, deployandoffernewservicestocustomersatscaleandatthesametime,significantlycutthe CapExandOpEx. ThisONOSusecasedemonstratesthepotentialofthisre=architectedcentralofficeatasmall scale.onos,itsapplicationsandopenflowenabledswitcheshelptransformthenetwork fabricofthecentralofficetosdnprovidingtheagilityrequiredforthenetworkfunctionsasa Service.Weexpecttobuildonthisusecaseintwoimportantdirections:demonstrateONOS canbethenetworkosforthere=architectedcentralofficenetworkintermsofscaleand performance;anddemonstratehowsdnandnetworkfunctionsasaservicefitwithinthe! samelargerarchitectureofthecentraloffice. 11!

12 SegmentRouting=EvolvingandImprovingMPLS! Today s IP/MPLS networks are complex and hard to manage. Label distribution, traffic engineering,andvpnsareverycomplexoperationsandservicesthatdependonacollectionof distributed protocols in the control plane. Furthermore debugging such networks is incredibly hard given synchronization and state=management issues between multiple protocols in the controlplaneandalocally=significantlabel=swappeddataplane.! TheIETFhasintroducedtheconceptofSegmentRouting(SR)forMPLS(knownbyitsIETFname SPRING).Itintroducesglobally=significantlabelsthatdon'tneedtobeswappedateachhop.It alsointroducessource=routingbasedonlabels,whicheliminatesdependenceoncomplex protocolslikeldpandrsvpforlabeldistributionandlspsetup.segmentroutingthussimplifies boththecontrolanddataplaneofmplsnetworks.whilesrcontinuestodependonanigpfor routingandlabeldistribution,itopensthepossibilityforanexternalcontrollertoprogramendto endtunnelsoriginatingatthesourcerouter. TheusecaseonSegmentRoutingisbeingpursuedincollaborationwiththeOpenNetworking Foundation'sSPRING=OPENprojectledbySauravDas.TheprojectdemonstrateshowSRcanbe realizedusingthesdncontrolplaneimplementedwithonosandansrapplication,working withbare=metalhardwareroutersbuiltonmerchantsiliconthatexiststoday.thissolutiondoes notuseadistributedigpembeddedintherouters.insteaditusesaroutingapplicationononos. Andtheapplicationprogramstheedge=routersandcore=routersforforwardingwithsegment routingrulesfordefaultroutingandpolicy=basedrouting.withonosprovidingthecontroland anapplicationmanagingthelabelsinthenetwork,networkoperatorscanexpresstheirpolicy requirementstothecontroller,andtheapptogetherwithonosimplementsthepolicyinthe IP/MPLSnetwork. Figure!8.!Segment!Routing*!! ThussegmentroutingwithONOSdemonstrateshowserviceproviderscanbuildontheMPLS dataplanewithoutthecomplexityofitscontrolplane.theycanhavebestofboth:simplicityof! thesrmplsdataplaneandagilityofthesdncontrolplane. 12! *"Source:"ONF"

13 CONCLUSION! OurgoalwithONOShasbeentocreateanopensourceSDNnetworkOSfortheServiceProvider andothermissioncriticalnetworks.onosisdesignedtoprovide(1)carriergradefeaturessuch asscalability,highavailability,performanceintermsofthroughput(applicationintentsper second)andlatency(timetoprocessnetworkevents);(2)northboundabstraction/apistomake iteasytocreatenewservicesusingonos thatistobringwebstyleagilitytonetworks;and(3) southboundabstractionwithdevice/protocolplug=inssoonoscanprovidesdncontrolfor OpenFlowenabledwhiteboxesaswellaslegacydevices.ThisenableseasymigrationtoSDN basedonwhiteboxes. OurworkonONOShasbeenguidedbyasetofusecasesproposedbyourpartnersthatinclude leadingserviceprovidersandvendors. TheONOSNovemberreleaserepresentsasolidnetworkoperatingsystemplatformtoseedan opensourceproject.however,westillhavesomewaystogototurnonosintoaproduction readyplatform.wehavetodevelopmanymoreusecases,continuetoimprovethe performance,enhancekeyfeaturesanddotrialsanddeploymenttoproviderealproofpoints. OpenSourcingONOSisacrucialmilestonebecauseitbringsinthebroadercommunitytojoinus inevolvingthisplatformandtrulydeliveringonourmissionofcreatingacarrier=grade,open sourcesdnosformissioncriticalnetworks.! 13!

14 ! 2014ON.Lab.AllRightsReserved. ABOUTON.LAB TheOpenNetworkingLab(ON.Lab) isa non=profitorganizationfounded bysdn inventors and leaders from Stanford University and UC Berkeley to foster an open source community for developing tools and platforms to realize the full potential of SDN. ON.Lab brings innovative ideas from leading edge research and delivers high quality open source platforms on which membersofitsecosystemandtheindustrycanbuildrealproductsandsolutions.on.labhasa teamof highly motivated andtalentedindividuals, with expertiseand astellar track record in industryandresearchinstitutions.on.lab steamisfocusedoncreatinghighqualityopensource toolsandplatformsthatbenefitandbringtruesdnvaluetothecommunity.! 14!