Monitoring Available Bandwidth of Underlying Grid Networks

Harnessing the complete power of grids depends, in part, on an application’s ability to adapt to changing network conditions. To this end, we are interested in monitoring available bandwidth of the underlying grid networks in the most accurate and least obtrusive way. Available bandwidth is either measured by actively injecting data probes into the network or by passively monitoring existing traffic, but there is a definite trade-off between the active approach, which is invasive, and the passive approach, which is rendered ineffective during periods of network idleness. Our solution is to develop the Wren bandwidth monitoring tool, which uses a hybrid approach to network monitoring that combines elements of passive and active techniques to offer accurate, timely available bandwidth measurements while limiting the invasiveness of probes. We have completed a packet trace facility, designed new passive bandwidth algorithms to measure the available bandwidth, and evaluated the effectiveness of these new algorithms in diverse environments. Our results indicate that a low overhead, passive monitoring system supplemented with active measurements can be built to obtain a complete picture of the network’s performance.