Presentation on theme: "Distribute what you can, centralize what you must!"— Presentation transcript:
1 Distribute what you can, centralize what you must! Narseo Vallina-RodriguezSupervisor: Jon CrowcroftQualcomm – Cambridge 22nd May 2013Apologize Jon; 2 day project meeting in LondonIdea: current centralised model: cloud-phone does not really work
2 Motivation The web is becoming mobile Apps rely on multiple online/cloud services (mobile mashup):CDNs (Akamai)Cloud services (Amazon WS)Authentication APIs (Oauth)Assisting sensors (A-GPS)Advertisement (AdMob, Burstly, Millennial Media, …)Push notifications (Google’s GCM)NAT punching for P2P (Skype)
3 Research questionHow do mobile apps’ cloud dependency impact on cellular network and battery life of mobile handsets?
4 outcomeWhen Assistance becomes Dependence: characterizing the costs and inefficiencies of A-GPS. Vallina-Rodriguez, Finamore, Grunenberger, Papagiannaki and Crowcroft. ACM SIGMOBILE MC2R (under review)Breaking for Commercials: Characterizing Mobile Advertising. Vallina-Rodriguez, Finamore, Shah, Grunenberger, Haddadi, Papagiannaki and Crowcroft. In ACM Internet Measurement Conference 2012(IMC'12)Energy Management Techniques in Modern Mobile Devices. Vallina-Rodriguez and Crowcroft. In IEEE Communications Tutorials and Surveys, 2012.When David can help Goliath: the case for cellular augmentation of wired networks. Vallina-Rodriguez, Erramilli, Grunenberger, Gyarmati, Laoutaris, Stanojevic, Papagiannaki, In ACM HotNets'12Signposts: End-to-End Networking in a World of Middleboxes. Aucinas, Chaudhry, Crowcroft, Probst Eide, Hand, Madhavapeddy, Moore, Mortier, Rotsos and Vallina-Rodriguez. In ACM SIGCOMM DEMO
5 Take away: moving to the edge! Mobile applications may abuse cellular networks: they cause network (signaling/channels/operational) and energy costs!Fetching content in a centralized fashion is not the only wayApps and OS must exploit locality and neighboring devices when possible!
7 Flashlinq/LTE-direct P2P wireless technologyPerfect candidate for transparent communication in the edge!Peer discovery (energy efficient)Expression-based discovery (service)Always-on background service with low duty-cycleSimilar to powering up a paging channel every X secondsCurrent prototype performance:Low-latency (<10 ms)Good throughput (~ 20 Mbps)Discovery (1~2 seconds)
10 Use case 1: Localized data A large fraction of mobile data is localWeatherNotificationsAdsApps use cellular networks and push notifications to fetch this contentHigh latencyNo delivery guarantees[Cellular data network infrastructure characterization and implication on mobile content placement, Xu et al. SIGMETRICS’2011]
11 Use case 1: Airport notifications SERVER (UK)NODE BGoogleGCM (Ir)RNCSGSNGGSNINTERNET
12 Use case 1: Airport notifications Traffic Pattern Heathrow App For Android (Flight Update)Energy Signaling Spectrum (HSPA)TCP/IP Push notification model is broken for local data:Frequent RNC promotions (some caused by TCP Heartbeats)Waste of energy, middleboxes/proxies memory and radio channels (+200K users/day, a lot of signaling traffic!)
13 Use case 1: Airport notifications PubSub model Low latencyNo net overheadEnergy efficientNo Middleboxes!SERVER (UK)FlashlinqNODE BGoogleGCM (Ir)RNCSGSNGGSNINTERNET
15 Use case 2: Collaborative A-GPS Assisting data (time, ephemeris, almanac, coarse location) downloaded from network:Reduces TTFF (usability)Temporal validity up to 2 weeks for ephemerisProblem: use of cellular network may impair performance and increase energy costs!
16 Use case 2: Collaborative A-GPS 2x current!Control-plane latency
17 Use case 2: Collaborative A-GPS Collaboration between devices in a P2P fashion:Context-awareness (sense environment so do not turn on AGPS indoors!)Share/pre-fetch assisting data (reduces latency to fetch data)Prototype for Nexus One:Pre-fetch and cache of assisting dataDevices can detect if they’re indoors in less than 10 secondsBlackbox. Hard to inject assisting data on chipsets (A-GPS is controlled by binary/proprietary files/drivers )
18 3. Wired-wireless integration Thinking beyond app-level use cases,Flashlinq is a perfect candidate for wired-wireless integration.
19 Use case 3: Wired-wireless integration 3G offloading to WiFi and femtocells:Reduce network trafficNo real benefit for users (unless volume cap in data-plan)Wired network can be constrained!Can cellular networks augment wired networks?Wired nets deployment is $$$Cellular nets have good coverage
20 Use case 3: Wired-wireless integration Cellular network can provide more capacity than wired ones (DSL)Spare capacity on cellular networkPowerboost for video- streaming appsUse-and-releaseDoes NOT work everywhere anytime!4.7 MbpsDSLAMDSL in rural/suburbs: far from DSLAMSpare capacity for small periods of time (HSPA)Powerboost (use and release)A2 Km2.8 MbpsGoogle Maps
21 Use case 3: Wired-wireless integration 2x downlink/5x uplink for most locations with 1 mobile deviceSimulation: 50% of the videos have a speed up factor of 10x2x downlink5x uplinkSome locations are congestedNevertheless, worst case shows that 50% apps can reduce by 10x the buffering time
22 Conclusions Current cloud-mobile model is not efficient Hyper-centralized: push notificationsLack of connectivity between handsets: missing opportunitiesCellular and wired networks are fully decoupledFlashlinq/LTE-direct can bring a new mobile paradigm!Energy and network efficientDistributedFlexible
23 Flashlinq limitations and extensions Transparent security/authentication mechanismsLessons to be learnt from the past: Bluetooth and WiFi-direct failed!Source of DoS/Privacy/Energy attacksGlobal Signpost-ish naming (OpenSource, DNSSEC based)Low-level radio details must be exposed to OS!Too much layering hides inefficiencies: e.g. A-GPS and 3GCross-layer optimizations are key (e.g. iPhone vs. Android)Incentives for operators?Reduce operational costs: better use of limited capacityLicensed frequency.. But there are few missing bits from my perspective as a developer that are being missing