Understanding users´ access failure and patience in large-scale P2P VOD systems

The Online P2P Video-on-Demand (VOD) streaming system has become one of the most popular Internet applications in recent years. Together with millions of users and tens of millions of workload, comes a big challenge for quality of service. This system´s time-free accessing strategy might bring about far more severe access failure than that caused by flash crowds in traditional IPTV. Why does access failure happen and how is a user´s patience towards it? It is a significant problem in system optimization and user experience improvement. This paper conducts a measurement study of access failure in a largest P2P VOD system named PPlive. We first analyze the statistic characteristics of channels´ access failure and its correlation with channels´ popularity. Then we propose a method to infer the causal factor of access failure for each user by mining users´ viewing behavior and channels´ broadcasting performance. Finally we discuss the distribution of user patience facing access failure and find that the initial successful accessing experience will increase user patience. All results can help design a new personalized recommendation balancing user interests and playback quality.