Proxy caching for peer-to-peer live streaming

1389-1286/$ see front matter 2009 Elsevier B.V doi:10.1016/j.comnet.2009.11.013 q This work has been supported in part by NSFC 60873253), NSFC-RGC Joint Research Project (20731 of China (2009CB320501), 863 Project of China ( Program for New Century Excellent Talents in Univ * Corresponding author. Tel.: +86 6 260 3064; fax E-mail addresses: [email protected] (K. Xu), (M. Zhang), [email protected] (J. Liu), [email protected] [email protected] (M. Ye). Peer-to-Peer (P2P) live streaming has become increasingly popular over the Internet. To alleviate the inter-ISP traffic load and to minimize the access latency, proxy caching has been widely suggested for P2P applications. In this paper, we carry out an extensive measurement study on the properties of P2P live streaming data requests. Our measurement demonstrates that the P2P living streaming traffic exhibits strong localities that could be explored by caching. This is particularly noticeable for the temporal locality, which is often much weaker in the conventional P2P file sharing applications. Our results further suggest that the request time of the same data piece from different peers exhibits a generalized extreme value distribution. We then propose a novel sliding window (SLW)-based caching algorithm, which predicts and caches popular data pieces according to the measured distribution. Our experimental results suggest that the P2P live streaming can greatly benefit from the proxy caching. And, with much lower overhead, our SLW algorithm works closer to an off-line optimal algorithm that holds the complete knowledge of future requests. 2009 Elsevier B.V. All rights reserved.