Accurate and efficient SLA compliance monitoring

Abstract

Service level agreements (SLAs) define performance guarantees made by service providers, e.g, in terms of packet loss, delay, delay variation, and network availability. In this paper, we describe a new active measurement methodology to accurately monitor whether measured network path characteristics are in compliance with performance targets specified in SLAs. Specifically, (1) we describe a new methodology for estimating packet loss rate that significantly improves accuracy over existing approaches; (2) we introduce a new methodology for measuring mean delay along a path that improves accuracy over existing methodologies, and propose a method for obtaining confidence intervals on quantiles of the empirical delay distribution without making any assumption about the true distribution of delay; (3) we introduce a new methodology for measuring delay variation that is more robust than prior techniques; and (4) we extend existing work in network performance tomography to infer lower bounds on the quantiles of a distribution of performance measures along an unmeasured path given measurements from a subset of paths. We unify active measurements for these metrics in a discrete time-based tool called SLAM. The unified probe stream from SLAM consumes lower overall bandwidth than if individual streams are used to measure path properties. We demonstrate the accuracy and convergence properties of SLAM in a controlled laboratory environment using a range of background traffic scenarios and in one-and two-hop settings, and examine its accuracy improvements over existing standard techniques.

An active measurement system for shared environments

“…The most well-known early study of these characteristics was reported by Bolot in [16]. While methodologies for measuring these quantities have been standardized by the IETF [8,9], improvements to these techniques continue to be developed [38,40]. Of particular relevance is the work by Sommers et al that highlights the need for real-time probe management in a multi-objective measurement context [39].…”

“…By virtue of its implementation, it is our hope that MAD can be widely deployed and used. We also believe that the design of MAD can inform future testbed development (e.g., GENI [7]) as well as infrastructures used to measure path properties in operational environments (e.g., for SLA compliance monitoring [40]). …”

Impact of access bandwidth on packet loss: A flow-level analysis

“…They developed a tool, BADABING, which reports loss measurements with a greater accuracy than its predecessors [15]. In another work, Sommers et al [14] analyzed delay and loss measurements from a SLA compliance perspective. Their main contribution is to find out congestion episode duration and their frequency of occurrence.…”

A Matrix-Based Method for Evaluating ISP Network Performance

“…The first approach is based on service-level agreements (SLAs) [3], and the second approach is based on the third-party systems [4][5][6].…”