A Framework for Multi-Objective SLA Compliance Monitoring

Service level agreements (SLAs) specify performance guarantees made by service providers, typically in terms of packet loss, delay, delay variation, and network availability. While many tools have been developed to measure individual aspects of network performance, there has been little work to directly address the issue of SLA compliance monitoring in an operational setting where accuracy, parsimony, and other related issues are of vital importance. This paper takes the following steps toward addressing this problem: (1) we introduce an architectural framework for integrating multiple discrete-time active measurement algorithms, an architecture that we call multi-objective monitoring; and (2) we introduce a new active measurement methodology to monitor the packet loss rate along a network path for determining compliance with specified performance targets which significantly improves accuracy over existing techniques. We present a prototype implementation of our monitoring framework, and demonstrate how a unified probe stream can consume lower overall bandwidth than if individual streams are used to measure different path properties. We demonstrate the accuracy and convergence properties of our new loss rate monitoring methodology in a controlled laboratory environment using a range of background traffic scenarios and examine its accuracy improvements over existing techniques.