Reducing Congestion Effects in Wireless Networks by Multipath Routing

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ICNP 2006. Reducing Congestion Effects in Wireless Networks by Multipath Routing. Presented by Dian Zhang Lucian Popa, Costin Raiciu, University of California, Berkeley. Outline. Problem statement and assumptions BGR congestion control mechanism IPS EPS Performance evaluation - PowerPoint PPT Presentation

Text of Reducing Congestion Effects in Wireless Networks by Multipath Routing

  • Reducing Congestion Effects in Wireless Networks by Multipath Routing

    Presented by Dian Zhang

    Lucian Popa, Costin Raiciu, University of California, BerkeleyICNP 2006

  • OutlineProblem statement and assumptionsBGRcongestion control mechanism IPSEPSPerformance evaluationConclusions

  • Overviewa point-to-point communication in a large Wireless Network

  • Overview

  • OverviewGoal: Split flows and reduce congestion by having less traffic in a contention/interference area.Improve overall throughputImprove fairness

  • Multipath Routing-related workWe need alternate paths to avoid congested hotspotsExisting solutions not satisfactoryWay pointsSimple Course GrainedTrajectory Based Forwarding [Niculescu03]Fine GrainedComplex and resource consuming

  • Biased Geographical Routing (BGR)IdeaInsert a bias inside the packet as a measure of the deviation from the greedy pathAchieve different paths by using different biasesbias = 0small biaslarge bias

  • BGR DetailsBias = AngleRoute greedy towards a close by point projected at bias angleDecrease bias at each stepQuadratic dependence on distance to destination Stop decreasing when it reaches zeroDestinationbias1

  • BGR DetailsBias = AngleRoute greedy towards a close by point projected at bias angleDecrease bias at each stepQuadratic dependence on distance to destination Stop decreasing when it reaches zeroDestinationbias2

  • BGR DetailsBias = AngleRoute greedy towards a close by point projected at bias angleDecrease bias at each stepQuadratic dependence on distance to destination Stop decreasing when it reaches zeroDestinationbias3

  • OverviewWe propose two algorithms to deal with congestion1. IPS - In-network Packet ScatterLocal algorithmLightweight no per flow stateSuited for short flows or light congestion2. EPS End-to-end Packet ScatterEnd to end rate control, relies on receiver feedbackSuited for long flows and widespread congestion

  • IPS (In-network packet scatter)Learn about congested neighbors

  • IPS (In-network packet scatter)Deviate uniformly traffic to congested nodes on three paths

  • EPS (End-to-end packet scatter)SourceDestination

  • EPS (End-to-end packet scatter)SourceDestinationCongested node

  • EPS (End-to-end packet scatter)SourcefeedbackDestination

  • EPS (End-to-end packet scatter)SourceDestination

  • EPS (End-to-end packet scatter)SourceCentral path is prioritizedDestinationExterior paths are less aggressive than the central one

  • EPS (End-to-end packet scatter)SourceMost traffic on least congested pathDestination

  • IPS+EPSThe two algorithms can be used IndependentlyCombined

  • ns2 setup400 nodes grid802.11 wirelessRandom source-destination pairsSuccess measured as received number of packets

  • Throughput vs Hop CountIncrease on AIMD(%)

  • Throughput vs No. Transmissions

  • TestbedMirage sensor network testbed~100 nodesBut too narrow interference on one side Thus, our main goal was to estimate in practice potential for throughput increase

  • Testbed metodologyThroughput ofvs

  • Testbed results% Increase in received packets for two BGR paths of 40 degree bias compared to single paths

    RateLQI 80LQI 82LQI 84LQI 8640 packets/s16711724233 packets/s120-1217-820 packets/s93-3-2-12

  • ConclusionsBGR An efficient and practical multipath algorithm for wireless networks with location informationIPS, EPSTwo mechanisms to increase fairness and throughput by multipath routingPractical tests

  • Thank you!ICNP 2006

    Single path greedy routing is shown as Simple while AIMD represents single path with rate control.The EPS + IPS combination increases long-range flow throughputs with around 70% as compared to single path transmission (both with and without AIMD).Given the large contention range (550m), we chose to split from the source only long-range flows flows wherethe distance between endpoints is larger than 1200m (6-8 hops). Shorter flows (less than 3 hops) are affected by exteriorpaths of split long-range flows. Short to medium range flows are more affected; 4-5 hops are most affected having a 15%throughput drop.

    Larger the network results should get better!Experimental results are consistent with the simulation results.