Content and context aware networking using semantic tagging(2)

Today’s model of networking primarily concentrates intelligence at the end hosts with the network itself offering a simple“best-effort”,“data agnostic ” communication medium. However, this paradigm has proven to be insufficient to meet todays needs co

timediastream(ie.generalize)orapartofaPFrame(ie.specialize)dependinguponthegranularityofthedescrip-tionprovidedandtheknowledgebaseoftherouter.

ItcanbearguedthatoneofthemostimportantreasonswhythecurrentInternetissowidelyacceptedanddeployedisprimarilyduetoitslayeredarchitecture.Thenetworkstackisimplementedasdifferentlayers,whereeachlayeroffersawellde nedfunctionality,iswellencapsulatedandcanbedevelopedindependentoftheothers.Wellde nedSer-viceAccessPoints(SAPs)arespeci edtoclearlyde nethedataandprimitivesexchangedbetweenadjacentlayersinthestack.Whilethisisthecurrentlyacceptedmodelofanetworkstack,recentyearshaveseenincreasedinterestintheareaofcrosslayeroptimizations.Theideahereistotrytoprovidealayerinthenetworkingstackwithadditionalcontextualinformationsothatamoreinformeddecisioncanbemadeonthedatahandledbythatlayer.Proponentsofthismodelarguethatwithsuchinteractions,bandwidthus-ageoptimization,moreef cientrouting,betterQoSguar-antees,betterpowerutilizationetc.canbeachieved.Ourframeworkprovidesthemeanstoexploitsuchcrosslayertechniquestoallow“hints”providedbyhigherlayerstobeusedlowerdowninthestackandlikewise,applicationsrun-ningontopoftheframeworkcanalsoregistertobenoti edofchangesinthenetworkconditionsthataremeaningfultothem.Alocalpolicyenforcementenginecontrolsthein-teractionsthatarepermissible.Throughthis,systemwidepoliciescanbedistributedthroughoutthenetworkthatareenforcedlocallyandacrossthenetworktocoordinatetheinteractionsanddatatransport.

Therestofthispaperisorganizedasfollows.Section2presentssomeoftherelevantbackground.Section3presentsourproposedapproach.Section4presentsresultsofoursimulationstudieshighlightingbene tsofcontentawarenessinthenetworkfollowedbyourconclusion.

atedassemblylanguagecalledSpannertoencodeacom-pleteprogramintoasingleIPv4orIPv6datagram.TheSwitchWareproject[4]takesasimilarapproachutilizingaspecializedlanguagecalledPLANwhosecapabilitiesarerestrictedtoonlyperforming“safe”operationsonanynode.ANTS[34]utilizesacombinationofmobilecode,demandloadingandcaching.Similartotheothermodels,anANTSnetworkconsistsofnodesrunninganANTSplatform,pack-etsarereplacedwithsmartcapsulescapableofexpressingmainlyforwardingroutinesandmechanismsarebuiltintothemodelforon-demandcodedissemination.Othersim-ilarapproaches[19]havefocusedonensuringquickjust-in-timecompilationofdownloadedcodetooptimizetheirperformancealongwithstaticlanguageveri cation.TheActiveSignalingProtocol(ASP)[13]takesadifferentap-proachtoactivenetworksbygoingawayfromthecapsulemodelandhavingdatapacketscarryareferencetosomeportablecodewhichcanbedownloadedonthe yandrunonanASPExecutionEnvironmentasnecessarytoenableanewactiveapplication.ActiveServices[5]takesanal-ternatemodeltointroductionofintelligenceintothenet-workbyrestrictingtheintelligencemainlytotheapplica-tionlayertherebypreservingtheroutingandforwardingse-manticsoftheInternetarchitecture.Asimilarapplicationlevelprocessingofuser-dataisconsideredin[10]tohandlecongestioncontrolinthenetwork.Thearchitectureallowsforapplicationstospecifyintra-networkprocessingbyus-ingActiveProcessingFunctionIdenti ers(APFI)sothatbandwidthallocatedcanbeintelligentlyreducedinaman-nertailoredtotheapplicationratherthangenerically.Whileactivenetworksareaverypowerfulparadigm,thereareseveraldrawbacksthathavehinderedtheiracceptanceandwidespreaddeployment.Theprimaryconcerniswithsecurityandprotectionagainstactiveroutersrunningmali-ciouscodehiddeninactivepackets.Approachesthatlimittheallowableoperationstoasafesubsetlimitthepowerofspecializedhandlingthatispossible.Anequallyimportantissueisthatnetworkoperatorsprefertohavecompletecon-trolovertheirnetworkandallowinguserde nedcodetobedownloadedandexecutedthatcouldpotentiallymakerout-ingdecisionsfordatastreamsisnotveryamenableforac-ceptance.Manyapproachesutilizedcustomizedplatformsandlanguagesraisinginteroperabilityconcerns.Also,thestateofthetechnologyinnetworkprocessorsatthattimepresentedchallengesforthetruerealizationofthisap-proach.Withourframework,weareworkingtowardsthesamegoalofmakingnetworkssmarterbutdoingsowithacompletelydifferentapproachthanactivenetworks.Ourframeworkallowsforthespeci cationof“whattypeofdata”is owingthroughthenetworkratherthanspecifying“howthatdatashouldbehandled”.Essentially,ourframe-workprovidesthehintstothenetworkfabricthroughcon-tentmetadatabuttheactualdecisionofhowbesttohandle2

2RelatedWork

2.1ActiveNetworks

ActiveNetworksisoneoftherevolutionaryapproachestoinjectintelligenceintothenetwork.Atanextremecase,thiscanbeviewedasanefforttoaugmentdatapacketswithcodefragmentscontainingspecializedprocessinglogicforhandlingthatpacket.“Active”routersexecutethecodecar-riedinthepacketallowinghighlycustomizedhandlingof owsorpackets.Thisarchitecturepermitsmassiveincreaseinthecomputationperformedwithinanetworkallowingforthedeploymentofnewservicesintothenetworkinatotallyseemlessandon-demandmanner.Severalprojectshavetakenthisapproachtoimpartingintelligenceintothenet-work.TheSmartPackets[29]approachutilizesaspecial-izedprogramminglanguagecalledSprocketandanassoci-

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