Real-time available-bandwidth estimation using filtering and change detection

This paper presents a filter-based method BART (Bandwidth Available in Real-Time) for real-time estimation of end-to-end available bandwidth in packet-switched communication networks. BART relies on self-induced congestion, and repeatedly samples the available bandwidth of the network path with sequences of probe-packet pairs. The method is light-weight with respect to computation and memory requirements, and performs well when only a small amount of probe traffic is injected. BART uses Kalman filtering, which enables real-time estimation. It maintains a current estimate, which is incrementally improved with each new measurement of the inter-packet time separation in a sequence of probe-packet pairs. It is possible to tune BART according to specific needs. The estimation performance can be significantly enhanced by employing a change-detection technique. An implementation of BART has been evaluated in a physical test network with carefully controlled cross traffic. In addition, experiments have been performed over the Internet as well as over a mobile broadband connection.