A Simple Model for Chunk-Scheduling Strategies in P2P Streaming
A Simple Model for Chunk-Scheduling Strategies in P2P Streaming
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DOI：
10.1109/tnet.2010.2065237
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发表时间：
2011-02
期刊：
影响因子：
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通讯作者：
Yipeng Zhou;D. Chiu;John C.S. Lui
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文献类型：
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作者：
Yipeng Zhou;D. Chiu;John C.S. Lui
点对点（P2P）流媒体试图实现可扩展性（如P2P文件分发），同时满足实时播放要求。这是一个具有挑战性的问题，仍然没有得到很好的理解。在本文中，我们描述了一个简单的随机模型，可以用来比较不同的下载策略，随机对等选择。基于这个模型，我们研究了支持的对等人口，缓冲区大小和播放连续性之间的权衡。我们首先研究两个简单的策略：稀有优先（RF）和贪婪。前者是一种众所周知的P2P文件共享策略，它通过尝试将文件的块尽可能快地传播给尽可能多的对等体来提供良好的可扩展性。后者是一种直观合理的策略，首先获得紧急块，以最大限度地提高播放的连续性，从对等体的本地角度来看。然而，在现实中，可扩展性和紧迫性都应该得到照顾。有了这个见解，我们提出了一个混合策略，实现了两个世界的最佳。此外，Mixed策略还带有一个自适应算法，可以根据动态对等体数量调整其缓冲区设置。我们验证我们的分析模型与模拟。最后，我们还讨论了建模假设和模型对不同参数的敏感性，并表明我们的模型是鲁棒的。
Peer-to-peer (P2P) streaming tries to achieve scalability (like P2P file distribution) and at the same time meet real-time playback requirements. It is a challenging problem still not well understood. In this paper, we describe a simple stochastic model that can be used to compare different downloading strategies to random peer selection. Based on this model, we study the tradeoffs between supported peer population, buffer size, and playback continuity. We first study two simple strategies: Rarest First (RF) and Greedy. The former is a well-known strategy for P2P file sharing that gives good scalability by trying to propagate the chunks of a file to as many peers as quickly as possible. The latter is an intuitively reasonable strategy to get urgent chunks first to maximize playback continuity from a peer's local perspective. Yet in reality, both scalability and urgency should be taken care of. With this insight, we propose a Mixed strategy that achieves the best of both worlds. Furthermore, the Mixed strategy comes with an adaptive algorithm that can adapt its buffer setting to dynamic peer population. We validate our analytical model with simulation. Finally, we also discuss the modeling assumptions and the model's sensitivity to different parameters and show that our model is robust.