Pseudo-DHT: Distributed Search Pseudo-DHT: Distributed Search Algorithm for P2P Video Algorithm for P2P Video Streaming Streaming December 15, 2008 December 15, 2008 Jeonghun Noh Jeonghun Noh Stanford University Stanford University Sachin Deshpande Sachin Deshpande Sharp Laboratories of America Sharp Laboratories of America
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Pseudo-DHT: Distributed Search Algorithm for P2P Video Streaming
Pseudo-DHT: Distributed Search Algorithm for P2P Video Streaming. December 15, 2008 Jeonghun Noh Stanford University Sachin Deshpande Sharp Laboratories of America. P2P Live Video Streaming. Relaying video using uplink bandwidth. Video source. - PowerPoint PPT Presentation
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Pseudo-DHT: Distributed Search Pseudo-DHT: Distributed Search Algorithm for P2P Video StreamingAlgorithm for P2P Video Streaming
December 15, 2008December 15, 2008
Jeonghun NohJeonghun NohStanford UniversityStanford University
Sachin DeshpandeSachin DeshpandeSharp Laboratories of AmericaSharp Laboratories of America
P2P Time-Shifted StreamingP2P Time-Shifted Streaming• Local storage to store fractions of the video• To locate video at arbitrary point, a query server may be used
3~6m
Seeking video of position 5m
7~11m
0~4m
A scalable distributed content search is desired
• The server can become a bottleneck as peer population increases• No dedicated server may be available
Pseudo-DHT: RetrievalPseudo-DHT: Retrieval• Seeking Video Chunk I
– Retrieve(i) may return a “miss”– K’ = i - (n-1)Δ (n=# attempts, Δ=offset base)– Repeat Retrieve(K’) with different keys until a hit occurs– Best-effort search, different from original DHT
Conclusion and Future WorkConclusion and Future Work• Proposed Pseudo-DHT
– Allows peers to register / retrieve video chunk in a scalable way– Slightly different from original DHT due to video continuity– Spreads out (key, value) items over the overlay
• P2TSS and Pseudo-DHT– Application to a P2P system– Thorough evaluation with analysis and simulations
• Future research topics– Changing Q dynamically according to peer population size– Considering heterogeneous peer uplink capacity for registration
Caching VideoCaching Video• Peers locally determine which portion to cache
• Distributed Stream Buffer (DSB)– Peer’s local buffer to hold a fraction of video– A finite size of cache (e.g., size of 2 to 4 minutes of video)– Independent of playback buffer
• Static contents in cache– No content change once the cache is full– Provides a bottom line performance