Patent ID: 7675856
Filing Date: 2010-03-09
Classification: H04L

Abstract:
1. A method of measuring available bandwidth over a network path between a source machine and a destination machine, the method comprising: receiving a series of probes, each containing a local timestamp; recording a respective destination time stamp for each probe indicating the time at which the probe was received at the destination device; computing a set of one way delays by differencing the local timestamp and the destination time stamp to compute the respective one way delay experienced by each probe over the network path; and calculating an estimate of bandwidth available on the network path based on the set of one way delays, wherein calculating an estimate of bandwidth available on the network path based on the set of one way delays further comprises: computing the cumulative distribution function of the set of one way delays; and identifying a knee of the cumulative distribution function, wherein identifying a knee of the cumulative distribution function comprises: calculating the slope of the cumulative distribution function before and after each of a plurality of points in the cumulative distribution function; determining the angle between the before and after slopes associated with each of the plurality of points; and identifying the point of the cumulative distribution function with the largest angle as the knee, wherein the point of the cumulative distribution function with the largest angle has an angle that is greater than or equal to a predetermined threshold, and wherein calculating an estimate of bandwidth available on the network path based on the set of one way delays further comprises calculating an estimate of bandwidth available on the network path based on the identified knee of the cumulative distribution function.