Efficiently monitoring bandwidth and latency in IP networks

Effective monitoring of network utilization and performance indicators is a key enabling technology for proactive and reactive resource management, flexible accounting, and intelligent planning in next-generation IP networks. In this paper, we address the challenging problem of efficiently monitoring bandwidth utilization and path latencies in an IP data network. Unlike earlier approaches, our measurement architecture assumes a single point-of-control in the network (corresponding to the network operations center) that is responsible for gathering bandwidth and latency information using widely-deployed management tools, like SNMP, RMON/NetFlow, and explicitly-routed IP probe packets. Our goal is to identify effective techniques for monitoring (a) bandwidth usage for a given set of links or packet flows, and (b) path latencies for a given set of paths, while minimizing the overhead imposed by the management tools on the underlying production network. We demonstrate that minimizing overheads under our measurement model gives rise to new combinatorial optimization problems, most of which prove to be NP-hard. We also propose novel approximation algorithms for these optimization problems and prove guaranteed upper bounds on their worst-case performance. Our simulation results validate our approach, demonstrating the effectiveness of our novel monitoring algorithms over a wide range of network topologies.