Striking The Balance Between Content Diversity and Content Importance in Swarm-Based P2P Streaming System

Striking The Balance Between Content Diversity and Content Importance in Swarm-Based P2P Streaming System

Chun-Yuan Chang, Cheng-Fu Chou* and Ming-Hung Chen

Presenter: Prof. Cheng-Fu Chou

National Taiwan University

ccf@cmlab.csie.ntu.edu.tw1OutlineIntroductionModel & Chunk Selection StrategiesPractical P2P Streaming System & Dynamic Strategy-SwitchPerformance EvaluationConclusion

2IntroductionSwarm-Based P2P StreamingSimilar to BitTorrentEncourage users to contribute its outbound bandwidth and storage to speed up content distribution.PPLive, PPStream, CoolStreaming and GridMedia, etc

3IntroductionTwo componentsOverlay constructionChunk swarming mechanismBuffer map exchangeChunk scheduling

The chunk IDs the peer possesses4IntroductionContent bottleneck problem

No content to exchange even if outboundbandwidth is sufficientMore diverse the content distribution is made, the less the content bottleneck is !!5IntroductionExisting approachesRarest-FirstE.g. CoolStreaming Infocom 2005RandomE.g. Chainsaw Infocom 2005Hybrid ones (Deadline-First + Rarest-First)E.g. Bitos Infocom 2006 and Prime Infocom 2007Network CodingE.g. R2 JASC 2007

6IntroductionSystem dynamicsPeer churnNetwork core congestion Variable source streaming rateContent diversity Random chunk lossContent ImportanceUnequal content importance

7IntroductionWith and without considering content importance

8OutlineIntroductionModel & Chunk Selection StrategiesPractical P2P Streaming System & Dynamic Strategy-SwitchPerformance EvaluationConclusion

9Model & Chunk Selection StrategiesSimple Model (ICNP 2007)

10Model & Chunk Selection StrategiesRecursive Formulation

11Rarest-First(RF)Priority B(1)>B(2)..

therefore

12Importance-First(IF)ch> clRarity is adopted to do a tie-break

13Importance-First(IF)

Only ch can compete to each other14Importance-First(IF)

15Numerical Result(1)

16Numerical Result(2)

17Simulation Result

18Short DiscussionComparisonScheduling efficiencyContent BottleneckIFGoodHighRFPoorLowHow can we support high scheduling Efficiency and maintain the scalability at the same time?19InsightsWhen population size is not large, we can enjoy throughput and scheduling efficiency simultaneouslyThere exist a good balance between content diversity and content importance20OutlineIntroductionModel & Chunk Selection StrategiesPractical P2P Streaming System & Dynamic Strategy-SwitchPerformance EvaluationConclusion

21Practical P2P Streaming SystemReceiver Side

22Practical P2P Streaming SystemSupplier Side

23Dynamic Strategy-SwitchAs a receiver:Detect if the number of retrieval chunks in the request window is zero. If it does, send a signal to itself. No scheduling process will be performed.If it does not , just subscribe to all desired chunks and assign each desired chunk to a peer who possesses the chunk in a random fashionAs a sender:Check if the event of content bottleneck is captured. If it does, conduct RAND on each requested packet. Otherwise, conduct IF on each requested packet.24OutlineIntroductionModel & Chunk Selection StrategiesPractical P2P Streaming System & Dynamic Strategy-SwitchPerformance EvaluationConclusion

25Performance EvaluationSimulator GridMedia ProjectSettings:

26Performance EvaluationVideo Trace:Encoded by H.264 (JM16.0)Concatenated by different types of CIF video sequences, which include high motion and low motion video sequencesFixed the quantization parameters (QP) for I,P,B frame in encoding27Metrics Delivery Ratio: the ratio of the number of chunks that arrive before playback deadline to the number of chunks that should arrive before playback deadline.PSNR (dB): the rendered video quality compared with the raw video sequence. The ffmpeg is used as our decoder.

28ComparisonsRAND: peers always serve the chunk in random fashionIF-IPB: peers always serve the chunk with highest priority with respect to IPB.PR-IPB: the prioritized random scheduling in [10]UL-IPB: the utility-like approach in [15]

29ComparisonsScalability

30ComparisonsScheduling Efficiency

31ComparisonsPSNR over time with 4,500 peers

underloadoverload32ConclusionPoint out the trade-off between content diversity and content importanceA simple but effective content bottleneck detector is proposed to strike the balance between content diversity and content importance33ch

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