Peer-to-peer Multimedia Streaming and Caching Service

1. Peer-to-peer Multimedia Streaming and Caching Service Jie WEI, Zhen MA May. 29

2. Outline • Metrics For Multimedia Streaming • Non P2P Solution • Peer to Peer Solution • Architecture • Caching • Streaming • Conclusion

3. Metrics For Multimedia Streaming • Low initial Delay • Small Delay Jitter During Playback • Minimum network bandwidth utilization

4. Non P2P Solution • Caching and Pre-fetching by Media Gateway • Achieve small initial delay and delay jitter during playback • Broadcasting Services • Achieve minimum server network bandwidth utilization

5. Motivation For P2P Architecture • Motivation of the peer-to-peer architecture • Exploits the proximity of clients • Minimizes the bandwidth utilization between the server and group of clients • Architecture • Assumes the group of peer-to-peer clients is connected via LAN • Each client not only receives streams from the server, but also acts as a proxy server.

6. S(0,t1) S(t3,t4) C2 C3 S(0,t4) Cache Manager S Cx C1 S(t1,t2) Architecture • One server,one cache manager and four nodes • s(i,j) represents segment of stream between byte i and j

7. Caching Management • Each client caches the retrieved stream and publishes its cache information to the cache manager • Each client monitors its own resource availability (eg. network bandwidth), updates all information to the cache manager

8. Streaming • Cache lookup • Send query message to cache manager for information of cached streams in peer clients • Streaming and Pre-fetching • With response from the cache manager, the client send streaming and pre-fetching requests to the peer clients or the server

9. Streaming • Timing diagram of the streaming and pre-fetching (requested by Ci)

10. Streaming Switching • In order to minimize the switching delay jitter, we should ensure a proper pre-fetching time • The pre-fetching time t is determined by, • Network bandwidth B • Network delay D

11. Pre-fetching Time • Case 1: B is larger than requested service rate, we only need to care about the network delay to ensure proper pre-fetching • Case 2: Bis smaller than , Buffer underflow might happen. We need to consider both network bandwidth and delay to ensure proper pre-fetching

12. How it achieves the metrics • Low initial Delay? • Small Delay Jitter During Playback? • Minimum network bandwidth utilization?

13. How it achieves the metrics • Low initial Delay By requesting to a peer client in the peer group, which caches the initial segments, it lowers initial delay than always requesting directly to the distant server

14. How it achieves the metrics • Small Delay Jitter During Playback? Minimize the switching delay jitter by calculating the right time point to do enough pre-fetching

15. How it achieves the metrics • Minimum network bandwidth utilization? P2P architecture reduces network bandwidth utilization and stream transfer time in the Client-Server architecture

16. Conclusion • Discussed a P2P Multimedia Streaming and Caching Model • P2P Multimedia Streaming and Caching Service can improve performance in all the three metrics.

17. Thank you