1. 1March -05 Jiangchuan Liu with Xinyan Zhang, Bo Li, and T.S.P.Yum Infocom 2005 CoolStreaming/DONet: A Data-Driven Overlay Network for Peer-to-Peer Live Media Streaming

2. 2March -05 Some Facts DONet – Data-driven Overlay Network CoolStreaming – Cooperative Overlay Streaming First release (CoolStreaming v0.9) May 2004 Till March 2005 Downloads: >100,000 Average online users: 6,000 Peak-time online users: 14,000 Google entries (CoolStreaming) : 5130

3. 3March -05 Outline Motivation Background and related work Design of DONet/CoolStreaming Implementation and empirical Study Future work

4. 4March -05 Motivation Enable large-scale live broadcasting in the Internet environment Capacity limitation ־Streaming: 500Kbps, server outbound band: 100Mbps ־200 concurrent users only Network heterogeneity No QoS guarantee

5. 5March -05 Client/Server: Poor scalability

6. 6March -05 IP multicast: Limited deployment

7. 7March -05 Collaborative Communications

8. 8March -05 Outline Motivation Background and related work Design of DONet/CoolStreaming Implementation and empirical Study Future work

9. 9March -05 Related Solutions Content distribution networks Expensive Not quite scalable for a large number of audiences Self-organized overlay networks Application layer multicast Peer-to-peer communications

10. 10March -05 Related Solutions Content distribution networks Expensive Live streaming (?) Self-organized overlay networks Application layer multicast Peer-to-peer communications

11. 11March -05 Application Layer Multicast Issue: Structure construction Tree NICE, CoopNet, SpreadIt, ZIGZAG Mesh Narada and its extension Multi-tree SplitStream

12. 12March -05 Application Layer Multicast (cont’d) Issue: Node dynamics Structure maintenance Passive/proactive repairing algorithms Advanced coding PALS (layered coding) CoopNet (multiple description coding)

13. 13March -05 Gossip-based Dissemination Gossip Iteration ־Sends a new message to a random set of nodes ־Each node does similarly in the next round Pros: Simple, robust Cons: Redundancy, delay Related Peer-to-peer on-demand streaming

14. 14March -05 Outline Motivation Background and related work Design of DONet/CoolStreaming Implementation and empirical Study Future work

15. 15March -05 Data-driven Overlay (DONet) Target Live media broadcasting No IP multicast support Core operations Every node periodically exchanges data availability information with a set of partners Then retrieves unavailable data from one or more partners, or supplies available data to partners

16. 16March -05 Features of DONet Easy to implement no need to construct and maintain a complex global structure Efficient data forwarding is dynamically determined according to data availability, not restricted by specific directions Robust and resilient adaptive and quick switching among multi-suppliers

17. 17March -05 Key Modules Membership manager mCache – partial overlay view Update by gossip Partnership manager Random selection Partner refinement Transmission Scheduler

18. 18March -05 Transmission Scheduling Problem: From which partner to fetch which data segment ? Constraints Data availability Playback deadline Heterogeneous partner bandwidth

19. 19March -05 Scheduling algorithm Variation of Parallel machine scheduling NP-hard Heuristic Message exchanged ־Window-based buffer map (BM): Data availability ־Segment request (piggyback by BM) Less suppliers first Multi-supplier: Highest bandwidth within deadline first Simpler algorithm in current implementation Network coding ?

20. 20March -05 Analysis on DONet Coverage ratio for distance k E.g. 95% nodes are covered in 6 hops for M=4 Average distance O(logN) DONet vs Tree-based overlay Much lower outage probability

21. 21March -05 Outline Motivation Background and related work Design of DONet/CoolStreaming Implementation and empirical Study Future work

22. 22March -05 PlanetLab Experiments Distributed experimental system DONet Module Console and automation Command dispatching and report collection Caveats Scalability Reproducibility Representability

23. 23March -05 Geographical Node Distribution May 24, 2004 # of Active Node: 200-300

24. 24March -05 Planet-Lab Result Data continuity, 200 nodes, 500 kbps streaming

25. 25March -05 Control overhead

26. 26March -05 Implementation: CoolStreaming First release: May 30, 2004 Source code: 2000-line Python Programming time: PlanetLab prototype: 2 weeks Export from prototype: 2 weeks Support formats: Real Video/Windows Media Platform/media independent Scale and capacity Total downloads: Peak time: 14000 concurrent users Streaming rate: 450-700kbps

27. 27March -05 User Distribution (June 2004) Heterogeneous network environment LAN, DSL, CABLE...

28. 28March -05 Online Statistics (Jun 21, 2004) Average Packet Loss around 1% - 5%

29. 29March -05 Observations Current Internet has enough available band to support TV-quality streaming (>450Kbps) Bottleneck: server, end-to-end bandwidth Larger data-driven overlay  better streaming quality Capacity amplification

30. 30March -05 Outline Motivation Background and related work Design of DONet/CoolStreaming Implementation and empirical Study Future work

31. 31March -05 Future of DONet/Coolstreaming Content Solution: DONet/Coolstreaming as a capacity amplifier between content provider and clients Virtually part of network infrastructure Enhancement Scheduling algorithm ־Simplified version ־Network coding Transport protocol ־TCP (?)

32. 32March -05 Future of DONet/Coolstreaming Enhancement (cont’d) User interface Combined with caching Combined with CDN ־Provide world-wide reliable media streaming service On-demand streaming

33. 33March -05 Q & A Thanks