OCARINA("OptimizationstoCompelAdoptionofRINA")

MichaelWelzlRINAWorkshop– ResearchDay

i2CATBarcelona23.5.2018

Projectoverview• 5-yearprojectfundedbyNorwegianresearchcouncil,started1October2016;1postdoc+3Ph.D.students– Focusedonperformance.Assumptions:1. RINAneedsto showfantasticperformance,2. RINAcan showfantasticperformance!

• 3mainWPs:cong.control,routing,Internetdeployment– RINAforcesustothinkdifferentlyaboutnetworkalgorithmssuchasroutingandcongestioncontrol

– E.g.,Internet-like"end-to-end"congestioncontrolcouldbeimplementedinaRINAnetwork,butthatwouldbeaverystrangeconfiguration 2

TwomajormistakesofInternetCC.1. Firstproducecongestion,thenreacttoit

– CC.isnotonlyaboutcontrollingaproblemafterithappens:CC.isaboutdeterminingtherightsendingrateatanytime

– Congestionisalsonotbinary,andlossanddelayarebadsignals– Solution: createameaningful"load"signalthatdoesnotembedaveryspecificalgorithm(givesomefreedomtodesigners)

2. Cluelessaboutunderlyinginfrastructure,bydesign– InevitableresultofInternetlayering:"IPovereverything"(goodidea),"TCPoptimizedtoblindlyrunoverIP"(badidea)

• "Cross-layer"solutionsshow:wecoulddobetter;buttheycanneverbestandardizedbecausetheydon'tfittheInternetmodel

• ...andPEPspragmaticallyimprovethingsbut"shouldn'texist"

– Solution: useper-DIFloops,workwithback-pressure 3

Addressingproblem#1:FixingECN

• Whyisitbroken?– Costincurredinthenetworkisadditiveperhop(seeNUMtheory),butcan'tre-mark amarkedpacketNote:costnotadditivewhenpacketsaredropped

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• OriginallynotamajorproblembecauseECNsignalshouldberare;butpoorsignal

• Better"load"signalinDCTCP-styleusage:instantaneousqueuemarking,countmarks/RTT

• Evenbetter"load"signalwhenmarkingbeforeaqueueevengrows(virtualQ)

Bettersignalquality,moreproblemswithmultiplelinks

ProblemsofusingECNas“load”

• Itisnotadditive;it’saproduct:– (pr:end-to-endmarkingprobability)– (pl:linkmarkingprobability)

• ModerncontrollerssuchasDCTCPconvergeathighmarkingprobabilities.

• Thetheory(e.g.NetworkUtilityMaximization(NUM))needsanadditivesignal;aproductvaluedeviatesmuchinhighmarkingprobabilities(>0.04)!

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OurSolution• ExtendingtheKKTtheoremtoincludefunctionsasmultipliers,andthen

useasmultiplier.– Withalotofmathandstabilityanalysisofcourse…

• Results:(assumingalogarithmicutility)

Advantages:1. Newsignalisaprettygeneralsolution;justconveys"load",andcould

(relatively)easilybeextendedtomulti-bit2. Newsignalisprobablygoodinputtoload-basedroutingtoo3. REDasanalready-deployedsolutioncanbeused;onlysmallchangesat

sendersandreceivers6

x(1):avg.rateofafive-hopflowx(2):avg.rateofaone-hopflow

Simulationresults

deviation(previoustheory)

Numericalresults

ourmethod

Howitworks

Applications• Obtainingutilityfunctionwhenthemarkingprobabilityishigh,e.g.DCTCP:

• Deflatingmarkingprobability– Playingwiththebaseoflog

• Andthepotentialofdealingwithvirtual("phantom")queues!

Addressingproblem#2:Per-DIFloopsPRISTINEbackground

• AsequenceofDIFsdoingTCPCC.ismuchlikeasequenceofsplit-TCPPEPs→canbebeneficial[1]– Examplesonthenextslides

• However,controlsusingrecursivequeuebasedfeedbackcanhavestabilityissues(+delayfrommultiplequeues)[2]

• Envisiontoaddressthiswithlogisticgrowthbasedcontrol[3]+new"fixed"ECN– Moreonthenextslides

1. PeymanTeymoori,MichaelWelzl,SteinGjessing,EduardGrasa,RobertoRiggio,KewinRausch,DomenicoSiracusa:"CongestionControlintheRecursiveInterNetworkingArchitecture(RINA)",IEEEICC2016,KualaLumpur,Malaysia,23-27May2016.

2. DavidHayes,PeymanTeymoori,MichaelWelzl:"FeedbackinRecursiveCongestionControl",13thEuropeanWorkshoponPerformanceEngineering(EPEW2016),Chios,Greece,5-7October2016.

3. PeymanTeymoori,DavidHayes,MichaelWelzl,SteinGjessing:"EvenLowerLatency,EvenBetterFairness:LogisticGrowthCongestionControlinDatacenters",IEEELCN2016,Dubai,UAE,Nov2016.

Horizontal:ConsecutiveDIFs

Topology: Results:

Vertical:StackedDIFs

Topology: Results:

1sender,1receiver:Sendersendsflow1(large)at0,andflow2(small)attime10.

LogisticGrowth:PopulationDynamicsProventobegloballyasymptoticallystable

N

Time

K = carrying capacity

∆N∆t

is maximized

∆N∆t

= 0

∆N∆t

= 0

1800 1900

r = growth rate

LGCinachain– MultipleLoopsFoodchainmodel:variousstabilityanalysesexist...

C1

1 2

router2

C2

router

C3L1,1 L2 L3

router1

L1,2

q1 reflectsthecongestionmeasureatbothrouters1and2

x1=x1+x1r(C1– x1– q1)

x2=x2+x2r(C2– x2– q2)

x3=x3+x3r(C3– x3– q3)

C1=min(x2,L1,1,L1,2)

C2=min(x3,L2)

WhataboutMachineLearning?

• Remy(offlinelearning),PCC+Vivace(onlinelearning)derive"optimal"TCPbehavior– ML!Likeinaself-drivingcar!

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Self-driving!

Limitationsofe2eCC• Therearemany...e.g.considerthe"verticalstacking"case:Remyetc.can'thelphereeither

• More"modern"example:especiallywith5G,PHYlinkcapacitycanchangealot,andquickly– TCPcannotquicklyreacttoit:TCPcan'tbesureasignalisfromthebottleneck

• IETFfailure;recentexample:"throughputguidance"– Onlysafetoreduce therate(andonlyifsignaltrustworthy)– SurveyofsuchideasthatfailedintheIETF:draft-dawkins-panrg-what-not-to-do

• RINAisanopportunitytoapplyMLtobetter-scopedproblems! 15

Deployment

• WecanconsiderRINA-under-IP,RINAoverlay,andRINA-IPgateways...

• Butwecanalsoconsider"switchingover"!– OnceahostdiscoversthatthewholepathtotheotherendisRINA-enabled,switch

– Today,often,pathsareshort(Google,FB,...arenotfarawayfromyou)

– TCP/IPareonlyrendez-vousprotocols– SomerecentIETFstandardscouldhelp

• AlittleironicJ 16

TransportServices(IETFTAPSWG)• Makesappsindependentofprotocoland networkinterface

– Finishedsurveyingandcondensingservicesprovidedby:TCP,MPTCP,UDP,UDP-Lite,SCTP,LEDBAT

– NowworkingonProposedStandard API+implementationguidance,withAppleamongothers;implementations:Apple,NEAT(opensource)

• APIproperties:callback-based,message-oriented– Hidesprotocols,butsupportsallfeaturesofallprotocolsabove+plan:QUIC– Someexampleprotocolproperties(somealso:protocol&pathselection):

Reliability,Ordering,Per-MessageReliability,0-RTTSessionEstablishment,RTXandICMPnotification,Checksumcoveragecontrol,Capacityprofile(normal,lowlatency,CBR,scavenger),Interfacetype,Multiplexing(multistreaming),RelativeNicenesswithingroup

– Varioussecurityparameters17

Interfacediagram(takenfrom:BrianTrammell,TAPS@IETF101)

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ProvisioningDomains(PvDs)(INTAREAWG)

• RouterAdvertisement(RA)optionfromfirst-hoprouterconveysFQDNthathostcanusetoretrieveextrainfoaboutnetworkaccesscharacteristicsviaHTTPoverTLSquery

• Applicationsthenselect(vialocalIPaddress)whichPvDtouse,andcanlearnconfig.paramsfortransportlayerandabove

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ExamplefromNEATproject

(GorryFairhurst,TomJones

(UniversityofAberdeen)

AndréVenne,EricBruneau

(Cisco))

Conclusion

• Congestioncontrol– RINA"forces"ustodoitinafundamentallydifferent,and(probably)inherentlybetterway

• betterthroughput,lesslatency

• Thiswillenableload-basedrouting– chanceformuchhigherthroughput

• ...andthereareinterestingdeploymentopportunities

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Thankyou!

Questions?

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