Measure and Model P2P Streaming System by Buffer Bitmap
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The document summarizes a measurement and modeling study of a peer-to-peer live streaming system. The study measures chunk rejection rates to characterize buffer behavior. It models the system in two phases, with each phase following an exponential distribution. The model is verified against real data to show it can accurately characterize the propagation of chunks through the peer-to-peer network.
Measure and Model P2P Streaming System by Buffer Bitmap
- 1. Measure and Model P2P Streaming System by Buffer Bitmap Yishuai Chen*, Changjia Chen, Chunxi Li Network Research Group, Telecom Lab, Beijing Jiaotong University
- 2. Index Introduction Measurement of PPLive Analysis Modeling
- 3. Mesh-Based P2P Streaming System Media Server Service Provider User 1 User 2 User 3 User 4 Chunk 1: Chunk 2
- 4. Local Buffer For local playback Sliding window like Limited Size 10s-100s
- 5. Buffer & Buffer Bitmap Measurable
- 6. Virtual Buffer End: Media Server Contain: the newest uploaded chunk Head: Peer buffer head Contain: the chunk shall be rejected Bitmap of virtual buffer: Peer’s buffer bitmap + ‘0’ appended until the buffer end
- 7. Measurement of PPLive Behavior: cache rejection sync with media server’s chunk uploading Rejection rate of a chunk = its uploading rate at media server Theorem 1. A fixed-duration buffer When constant rate uploading, fixed length buffer Smoothly transit when rate changes
- 8. Analysis Method Bitmap Matrix Chunk Position: m Occupancy Probability: P m
- 9. P m : is a network characteristic Peers in same network has similar P m
- 10. N ( t ) chunk uploaded at t =0 N(t) ： the amount of peers who have obtained this chunk at time t Reflects the propagation procedure of a chunk P m = N ( m/r )/ M 0 M 0 : network size r : playback rate.
- 11. Model Two phases Each phase is exponential
- 13. Thanks!