Modeling available bandwidth for an efficient QoS characterization of a network path

Abstract

Estimating the reliability of an end-to-end network path is critically important for applications that support remote real-time task execution. Available bandwidth, which is defined as a minimum spare capacity of links constituting a network path, is an important QoS characteristic of the path. In this work we demonstrate a new approach to modelling available bandwidth behavior from a time-series analysis prospective. In particular, we introduce a notion of crossing probability-the probability that available bandwidth drops below the QoS critical threshold for the period of time required for a real-time task execution. We estimate "crossing probability" by an application of the ARCH 2 (AutoRegressive Conditional Heteroscedasticity) model to available bandwidth behavior. We estimate model coefficients β 0 and β 1to quickly output "crossing probability" for arbitrary values of threshold and length of the real-time task. The model was evaluated on real bandwidth measurements across multiple network paths. © IFIP International Federation for Information Processing 2005.