Abstract

Service Level Agreements (SLAs) define the performance guarantees made by Internet Service Providers (ISPs) in terms of packet delay, loss, variation and network availability. In this talk, I will describe our work on SLA compliance monitoring, which focuses on assessing whether the performance characteristics in a service provider network are within specified bounds. To address this problem we have developed a comprehensive set of active probe-base measurement methodologies that enables accurate and efficient assessment of 1) packet loss rate, 2) mean delay, 3) confidence intervals for delay quantile estimation, and 4) delay variation (ie. jitter). We implement these methods in a tool called SLAm, which we use to demonstrate the capabilities of our approach in a set of controlled laboratory experiments using different topologies and background traffic scenarios. We also extend the use of SLAm to the practical problems of detecting and localizing the occurrences of SLA violations in provider networks. This requires additional methods for selecting which paths to probe at a given point in time and then identifying the links on a path that are contributing to a violation event. We use a set of simulation-based experiments to show that these methods are able to accurately detect and localize performance violation events in a timely fashion and with lower probe overhead than prior methods.

Bio: Paul Barford an associate professor in computer science at the University of Wisconsin-Madison. He received a BS in electrical engineering from the University of Illinois and a PhD in computer science from Boston University. He is the founder and director of the Wisconsin Advanced Internet Laboratory. His research is focused on developing new techniques and tools for gathering information on the structure and dynamic behavior of the Internet. He is also focused on developing new methods for protecting networks and systems from malicious attacks, and is the founder and CEO of Nemean Networks, a network security start-up company located in the Madison area. Prof. Barford has authored numerous publications in highly competitive journals and conferences. His work is funded by the NSF , DHS, ARO , NSA and companies including Cisco, Intel, Sun and others. He has served on committees of many conferences including ACM SIGCOMM , SIGMETRICS (‘10 TPC chair), IMC (‘06 TPC chair), CCS and USENIX Security. He is the Chair of the NSF /GENI Network Measurement Working Group, a member of the ACM Internet Measurement Conference steering committee, an associate editor of IEEE /ACM Transactions on Networking, and a member of the Board of Directors of the National LambdaRail.