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
[email protected] & 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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