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1、 Optimizing Several Critical Properties of P2P Streaming Systems by Zhenhua LI supervised by Prof. Guihai Chen A dissertation submitted to the Graduate School of Nanjing University for the Degree of Master of Engineering Department of Computer Science and Technology Nanjing University May, 2008 ? ?
2、? P2P?P2P? ?Skype?PPLive?PPStream? ? ? ? ?2008?1?17?21? ?P2P? ?29.91%?P2P? ? P2P? ? ? ?P2P?3?1? ?2? ?3? ? ?1?P2P?ContinuStreaming? ?DHT?Gossip? ?ContinuStreaming? ?P2P? ?Gossip?P2P?CoolStreaming? ContinuStreaming?4%?1.0? ?2?P2P? ? ? ? ? ? ? ? P2P? ?20%-30%? ? ? ? ?3?P2P? ? ? ? ? ? ? ? ? ? ?P2P?P2P?G
3、ossip? ? Master Degree Thesis: Abstract Abstract In recent years, P2P streaming systems have been widely used by a great number of Internet users. Typical P2P streaming systems include Skype, PPLive, PPStream and so on. Both in the areas of Internet audio and Internet video, there exist tens of comp
4、anies competing severely. The competition situation is not only accelerating technology development in IT industry, but also providing guaranteed value for the research work in academia. According to the 21st statistics report of the development status of China Internet lately published by the China
5、 Internet Network Information Centre, among the several primary ways in which China Internet users watch Internet video programs, downloading through P2P streaming software occupies a ratio up to 29.91%, which is close to 1/3. Therefore, P2P streaming has become an area which owns a huge user base a
6、nd an area filled with research potential and significance. P2P streaming systems have many properties that are worth research work. From the point of user experience, there are some properties such as playback continuity, playback data rate, startup delay, source switch time, bandwidth utilization,
7、 system fault tolerance, etc. From the point of system designer, there are some properties such as location efficiency, end-to-end delay, data throughput, topology awareness, load balance, system maintenance overhead, control overhead, scalability, etc. This paper focuses on three critical propertie
8、s of P2P streaming systems: (1) playback continuity, (2) source switch delay, (3) system fault tolerance. It proposes, designs and evaluates the performance of corresponding optimization schemes for the above three critical properties. The main creative research results of this paper can be summariz
9、ed as follows: (1) This paper designs ContinuStreaming, a gossip-based P2P streaming system with high playback continuity. With the help of DHT, data segments which are likely to be missed by the gossip-based data scheduling can be quickly fetched by the on-demand data retrieval so as to guarantee c
10、ontinuous playback. We discuss the results of both theoretical analysis and comprehensive simulations on various real-trace overlay topologies to demonstrate the effectiveness of our system. Simulation results show that ContinuStreaming can increase the playback continuity very close to 1.0 with les
11、s than 4% extra overhead. (2) This paper models the source switch process in P2P streaming systems and formulates it into an optimization problem. Then we propose a practical greedy algorithm that can approximate the optimal solution by properly interleaving the data delivery of the old source and t
12、he new source. The simulation results on various real-trace overlay topologies show that our proposed algorithm outperforms the normal source switch algorithm by reducing the source switch time by 20%-30% without bringing extra communication overhead, and the reduction ratio tends to increase when t
13、he network scale expands. (3) This paper suggests the concept of partition node to describe the topologically-critical nodes of the underlying overlay network of P2P streaming systems. The failure of a partition node may potentially lead to overlay partitioning. Then we propose a simple, effective and distributed Master Degree Thesis: Abstract method to
