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

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

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

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

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.

Architecture One server,one cache manager and four nodes s(i,j) represents segment of stream between byte i and j S(0,t 4 ) S(0,t 1 ) S(t 3,t 4 ) S(t 1,t 2 ) C1C1 C2C2 C3C3 CxCx S Cache Manager

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

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

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

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

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: B is smaller than , Buffer underflow might happen. We need to consider both network bandwidth and delay to ensure proper pre-fetching

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

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

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

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

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

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