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LOW-LATENCY VIDEO STREAMING OVER PEER-TO-PEER NETWORKS

LOW-LATENCY VIDEO STREAMING OVER PEER-TO-PEER NETWORKS. Eric Setton Jeonghun Noh Professor Bernd Girod Information Systems Laboratory Stanford University. Motivation. Challenges of P2P streaming Limited bandwidth Unreliable peers Related work Tree-based p2p :

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LOW-LATENCY VIDEO STREAMING OVER PEER-TO-PEER NETWORKS

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  1. LOW-LATENCY VIDEO STREAMING OVER PEER-TO-PEER NETWORKS Eric Setton Jeonghun Noh Professor Bernd Girod Information Systems Laboratory Stanford University

  2. Motivation Challenges of P2P streaming • Limited bandwidth • Unreliable peers Related work • Tree-based p2p : • End System Multicast (single tree) [Chu, Rao, Zhang, ACM SIGMETRICS 2000] • COOPNET (central server, multiple trees) [Padmanabhan et all, NOSSDAV, 2002] • Mesh-based (Gossip-based) p2p : • Coolstreaming [Zhang, Liu, Li and Yum, MMSP & INFOCOM 2005] Our Goal : Low-latency P2P video streaming

  3. Outline • Low-latency P2P protocol • Join / rejoin procedure • Experimental setup • Performance • Prioritized transmission • Content / network-aware prioritization • Simulation Results

  4. Video stream … … Multiple Tree Construction

  5. Video stream … … Join Procedure Initial join • Contact video source • Receives peer list, number of trees Probe peers Connect to multicast trees • Parent selection factor • Available bandwidth • Minimize tree height • Maximize diversity

  6. Disconnect / Rejoin Procedure Parent of yellow tree is down Parent leave is detected Retransmissions requested Yellow tree is recovered 3 trees Yellow tree is down?

  7. Downlink Uplink Percentage 512 Kb/s 256 Kb/s 56% 3 Mb/s 384 Kb/s 21% 1.5 Mb/s 896 Kb/s 9% 20 Mb/s 2 Mb/s 3% 20 Mb/s 5 Mb/s 11% Experimental Setup • Network/protocol simulation in ns-2 • 300 active peers • Random peer arrival/departure average: ON (4.5 min)/OFF (30 sec) • Typical access bandwidth distribution • Over-provisioned backbone • Delay: 5 ms/link + congestion • Video streaming • H.264/AVC encoder @ 250 Kb/s • 15 minute live multicast [Sripanidkulchai et al.,2004]

  8. Join and Rejoin Latencies Simulations over ns-2, 300 peers Number of trees: 3 Retransmissions enabled

  9. Protocol Scalability Simulations over ns-2 Video traffic Control traffic Protocol overhead

  10. Benefit of Diversity Distribution of peer bandwidth Video encoding rate : 250 Kb/s Over-provisioning factor : 15%

  11. Benefit of Diversity

  12. I B P P P B B Network / Content-Aware Prioritization • Scheduler iteratively selects 7 1 6 1 4 1 2 Sender

  13. Network / Content-AwarePrioritization 4dB 5dB 2.5dB 5dB Number of trees: 4 Retransmissions enabled

  14. 36 Parallel Viewsout of 75 peers Network/content awareprioritization 33.71 dB No prioritization 30.17 dB H.264 @ 250 Kb/swith 0.8 second playout deadline

  15. 36 OverlappedViewsout of 75 peers Network/content awareprioritization 33.71 dB No prioritization 30.17 dB H.264 @ 250 Kb/swith 0.8 second playout deadline

  16. Conclusions • Peer-to-peer control protocol • Tested with up to 3000 peers in ns-2 • Light-weight and scalable • Low start-up and tree repair time • Network/content-aware prioritization • Adapts to packet importance and tree topology • Gains up to 5dB with small playout deadline

  17. Probes extra peers regularly Extra Peer Pool for Fast Rejoin One of multiple trees The red tree parent leaves Chooses a new parent Advantage : - Keep Parent Diversity - Less packet drop Disadvantage : - Increased control traffic - Weak to large-scale disconnect

  18. I B B P P … … Receiver-Driven Content-AwareRetransmission Requests Parent 1 Child P Parent 2 fails Video Buffer • Determine missing packets • Iteratively request most important packet • Limit number of unacknowledged retransmissions

  19. Content-ObliviousRetransmissions Without retransmissions % peersconnected to all 4 trees With content-oblivious retransmissions % peersconnected to all 4 trees

  20. Receiver-Driven Content-Aware Retransmissions Without retransmissions % peersconnected to all 4 trees With receiver-driven CoDiO light % peersconnected to all 4 trees

  21. Video and Network Aware Design • Child peers (Receivers) • Receive video stream from parent peers • On requesting retransmissions • Compute expected video quality improvement • Compute expected network congestion • Parent peers (Senders) • Send video stream to child peers • On scheduling packets to transmit • Compute importance of each packet • Compute expected network delay

  22. Benefit of Diversity Video source : 250kbps (Mthr & Dthr) Retransmissions enabled

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