An approximate stochastic analysis of the packet-pair probing technique for available bandwidth estimation

The packet-pair probing algorithm for network-bandwidth estimation is examined and an approximate model is proposed for predicting its behaviour. The model replaces the Poisson arrival process with a Gaussian distribution and resolves the queue-size profile into two separate components: A transient component representing the buffer-emptying process and an equilibrium component representing the return to steady-state behaviour. Comparison with discrete-event simulation results shows that the model is accurate in single-hop paths when utilization is <= 70% when the cross-traffic packets are <= 1/2 the size of the probe packets. When extended to two-hop paths, the model remains accurate for smaller 2 cross-traffic packets (<= 1/10 - 1/5 the probe-packet size). Copyright (C) 2008 John Wiley & Sons, Ltd.