IEEE Ninth International Conference on Peer-to-Peer Computing, 2009
Characterizing user churn has become an important topic in studying P2P networks, both in theoretical analysis and system design. Recent work has shown that direct sampling of user lifetimes may lead to certain bias (arising from missed peers and round-off inconsistencies) and proposed a technique that estimates lifetimes based on sampled residuals. In this paper, however, we show that under non-stationary arrivals, which are often present in real systems, residual-based sampling does not correctly reconstruct user lifetimes and suffers a varying degree of bias, which in some cases makes estimation completely impossible. We overcome this problem using two contributions: a novel non-stationary ON/OFF churn model and an unbiased randomized residual sampling technique for measuring user lifetimes. The former allows correlation between ON/OFF periods of the same user and exhibits different join rates during the day. The latter spreads sampling points uniformly during the day and uses a novel estimator to reconstruct the underlying lifetime distribution. We finish the paper with experimental measurements of Gnutella and discussing reduction in overhead compared to direct sampling methods.
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Place of Publication
peer-to-peer computing, random processes, sampling methods, statistical analysis, large-scale P2P system, nonstationary ON-OFF churn model, nonstationary arrival, robust lifetime measurement, system design, theoretical analysis, unbiased randomized residual sampling technique, user lifetime, Delay, Internet, Large-scale systems, Life estimation, Lifetime estimation, National electric code, Robustness, Sampling methods, System analysis and design, Visualization
Wang, Xiaoming; Yao, Zhongmei; Zhang, Yueping; and Loguinov, Dmitri, "Robust lifetime measurement in large-scale P2P systems with non-stationary arrivals" (2009). Computer Science Faculty Publications. 2.