Measuring Available Bandwidth: pathChirp's Chirp Train Structure Remodeled

摘要

Measuring available bandwidth over a network path is required by many applications including end-to-end admission control and server selection. In order to measure the available bandwidth, the end hosts need network information, such as packet delay, at intermediate systems. Several techniques have been proposed to address this problem. We have selected the most recently proposed algorithm called pathChirp and proposed an alternative approach. The main goal of pathChirp is to get the delay information at the intermediate systems by using the concept of self-induced congestion (which uses chirp train packets) in order to estimate the available bandwidth. However there are scenarios where pathChirp cannot provide accurate available bandwidth. We use the pathChirp mechanism as our underlying tool and modify its structure of chirp train. In the modified structure, the rate of the odd inter-chirp packet will be the same as the rate of previous even inter-chirp packet. Additionally, rate of inter-chirp packets will be increased exponentially with even power rather than both even and odd power as done in pathChirp scheme. Purpose of this new structure is to capture more network information using three different time-shifted chirp trains, and subsequently to find a better estimate for the available bandwidth. Our theory and simulation results support this claim.