On the 95-Percentile Billing Method

Abstract. The 95-percentile method is used widely for billing ISPs and websites. In this work, we characterize important aspects of the 95-percentile method using a large set of traffic traces. We first study how the 95-percentile depends on the aggregation window size. We observe that the computed value often follows a noisy decreasing trend along a convex curve as the window size increases. We provide theoretical justification for this dependence using the self-similar model for Internet traffic and discuss observed more complex dependencies in which the 95-percentile increases with the window size. Secondly, we quantify how variations on the window size affect the computed 95-percentile. In our experiments, we find that reasonable differences in the window size can account for an increase between 4.1% and 42.5% in the monthly bill of medium and low-volume sites. In contrast, for sites with average traffic rates above 10Mbps the fluctuation of the 95-percentile is bellow 2.9%....

• Type: Conference
• Year: 2009
• Where: PAM
• Authors: Xenofontas A. Dimitropoulos, Paul Hurley, Andreas Kind, Marc Ph. Stoecklin
• Keywords: 95-percentile Method, Aggregation Window Size, Computer Networks, PAM 2009, Window Size