: Improving Internet Telephony Quality Using Predictive...
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VIA: Improving Internet Telephony Quality Using Predictive Relay Selection Junchen Jiang, Rajdeep Das, Ganesh Ananthanarayanan, Philip A. Chou, Venkata N. Padmanabhan, Vyas Sekar, Esbjorn Dominique, Marcin Goliszewski, Dalibor Kukoleca, Renat Vafin, Hui Zhang 1
Transcript of : Improving Internet Telephony Quality Using Predictive...
VIA:ImprovingInternetTelephonyQualityUsingPredictiveRelaySelection
Junchen Jiang,Rajdeep Das,GaneshAnanthanarayanan,PhilipA.Chou,Venkata N.Padmanabhan,VyasSekar,Esbjorn Dominique,Marcin
Goliszewski,Dalibor Kukoleca,Renat Vafin,HuiZhang
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Keytakeawaysinoneminute
Onefifth ofcallsusepathswithpoornetworkperformance
“ManagedOverlay”couldalleviateoverhalfofcallsonthesepaths
VIA:Data-drivenrelayingcanrealizemostManagedOverlay’spotential
Westudied430millionSkypecallsandfound…
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Million
Peak#ofusersconcurrentonlineonSkype
Internettelephonyiseverywhere!
MoreappsfocusingonInternettelephony
https://blogs.skype.com/2013/04/03/thanks-for-making-skype-a-part-of-your-daily-lives-2-billion-minutes-a-day/
Rapidgrowthoverthelastdecade
https://www.statista.com/chart/1417/skype-usage/3
Callqualityissensitivetobadnetworkperformance
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Thresholdsofpoornetworkperformance
Datasets:Avg RTT,lossrate,jitterforeachcallof430millionSkypecallsSmallfractionhasuser-providedqualityscores
320ms 1.2% 12ms
Manycallshavepoornetworkperformance
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17%17%12%Onefifth ofcallshavepoornetworkperformance
Ourgoal:AlleviatepoornetworkperformanceforSkype
Outline
• Problem: NetworkperformanceofSkypeisbad
è Opportunity: ManagedOverlayhashugepotential
• Solution: VIAforoptimalrelayselection
• Evaluation: VIAisclose-to-optimal
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RevisitingOverlayNetworksbyManagedOverlay
ManagedOverlayhasnewbenefits• World-wide distributedDCs asrelays• Wellconnected• Deployedbymanyproviders• Single administrativeentity
HowmuchcanInternettelephonybenefitfromit?
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Selectingthebestrelayoption
Keyistoselectthebestrelayoption(direct,one-relay,ormulti-relay)
Q1:Doespickingbestrelayoptionhavesignificantimpact?Q2:Ifso,howtopickthebestrelayoption?
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Directpath
One-relayhop
Multi-relayhops
ManagedOverlayhashugepotentialbenefit
Substantialfractionofbad-performancecallscould bealleviated
Consideranoraclethatpicksthebestrelayoptionforeachsrc-dst ASpairin24hours
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RTT Loss Jitter Atleastonebad
Poorperformance:RTT>320ms;Lossrate>1.2%;Jitter>12ms
%calls“Bad”è “Good”
Outline
• Problem: NetworkperformanceofSkypeisbad
• Opportunity: ManagedOverlayhashugepotential
è Solution: VIAforoptimalrelayselection
• Evaluation: VIAisclose-to-optimal
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VIA:RealizingthebenefitofManagedOverlayusingCentralizedPredictiveControl
Qualityofexistingcalls
Relayselection
VIAControlAlgorithmPredictthebestrelayoptionbased
onothercalls’performance
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Strawman 1:Pureprediction-based
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Uselong-termhistorytopredictperformance
Relayoptions
Anewcall
Problem:CallperformancehasgreatinherentvarianceE.g.,predicting“nextday”using“lastweek”leadstoover30%erroronlatency.
CallhistoryQualityprediction
Strawman 2:Pureexploration-based
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Inashorttimewindow,explorerelayoptions,thenexploitthebestone
Relayoptions
CallsofoneASpairperday
Problem:Calldistributionishighlyskewed“#ofactualcalls>>#ofrelayoptions”NOTtrueformostASpairs
Keyidea:Guidedexploration
Prediction-based Exploration-basedXORStrawmenVIA
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00.20.40.60.81
0 1 2 3 4 5 6 7 8 9Prob
abilityofthe
best
relaybe
inginto
pk
k
Topk canbemoreeasilypredictedandcanbemore efficientlyexplored!
VIA’sidea:GuidedExplorationRoughpredictioncanstillidentifytopk candidates,whichcanbeexploredefficiently.
Predictingtop1istoohard
Step1:Prediction-basedpruning
Latency
Confidenceintervalofqualityprediction
Top-kcandidates
Focusonrelayoptionswhoseconfidenceintervalsarebetterthanthoseofothers.
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Callhistory
Upperboundof“blue”and“yellow”isbetterthanthelowerboundof“green”and“red”
Step2:Exploringtop-kcandidates
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Multi-armedbanditprocessUpperConfidenceBounds(UCB1)
Reward
OurproblemlookslikeMABUCB1withdomain-specifictwists
Reward
Reward
Howtomaximizerewards?
Howtominimizelatency?
UCB1:AlwayspicktheonewiththehighestUCB
Puttingthemtogether:GuidedExplorationinaction
Callhistory
Performancemeasurements
Tomography-basedcoverageexpansion
Predictiveselectionoftopk candidates
ModifiedUCB1onthetopk candidates
Toexploremorerelays Real-timerelayselection
Runspercall
Prediction-basedPruningUpdateseveryT hours
Top-k candidatesperASpair
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Allrelayoptions
Moreinourpaper
• Budgetedrelaying
• Networktomography
• Granularityofprediction
• Internationalvs.domesticcalls
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Outline
• Problem: NetworkperformanceofSkypeisbad
• Opportunity: ManagedOverlayhashugepotential
• Solution: VIAforoptimalrelayselection
è Evaluation: VIAisclose-to-optimal
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VIAachievesclose-to-optimalperformance
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Poorperformance:RTT>320ms;Lossrate>1.2%;Jitter>12ms
%calls“Bad”è “Good”
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RTT Loss Jitter Atleastonebad
Optimal VIAPrediction-based Exploration-based
BenefitvariesacrossASes
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SourceAS1 SourceAS2 SourceAS3
Oracle VIA
Substantialimprovement
Limitedroomforimprovement
Roomforfurtherimprovement
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%calls“Bad”è “Good”
Conclusion
• Internettelephony isheretostay• Problem:Onefifthofcallshavebadnetworkperformance.
• Opportunity:ManagedOverlaycould significantlyreducebad-performancecalls.
• Challenges:OptimalrelayselectionPurepredictionandpureexplorationwon’twork!
• Solution:VIAcanrealizemostofthebenefitofManagedOverlay.Keyidea:Guidedexploration:
Predictivepruningofrelayoptions+Explorationovertopkcandidates22
