Effective bandwidth shaping: a framework for resource dimensioning

Abstract

Effective bandwidths is a statistical descriptor in the context of stochastic models for statistical sharing of resources. It is generally known [C.-S Chang and J.A. Thomas, August 1995] that effective bandwidths assigned to independent flows being multiplexed behave additively. Furthermore it has been shown [D. Wischik, 1999] that under the many sources limiting regime, an effective bandwidth assigned to a flow passing through a switch is not changed, and inductively a flow has the same effective bandwidth through the entire network. If all flows feeding a network under consideration have well defined effective bandwidths and QoS demands, resource dimensioning can be done based on simple large deviation principles. We address the problem of specifying and limiting effective bandwidths of arriving flows by introducing a new shaping and policing algorithm based on an on-line effective bandwidth estimator. The presented algorithm's functionality is verified by both synthetic and real data traces. Finally the performance of proposed algorithm variants is discussed.