USITS 2001 Abstract
Nettimer: A Tool for Measuring Bottleneck Link Bandwidth
Kevin Lai and Mary Baker, Stanford University
Abstract
Measuring the bottleneck link bandwidth along a path is
important for understanding the performance of many Internet
applications. Existing tools to measure bottleneck bandwidth are
relatively slow, can only measure bandwidth in one direction, and/or
actively send probe packets. We present the nettimer
bottleneck link bandwidth measurement tool, the libdpcap
distributed packet capture library, and experiments quantifying their
utility. We test nettimer across a variety of bottleneck
network technologies ranging from 19.2Kb/s to 100Mb/s, wired and
wireless, symmetric and asymmetric bandwidth, across local area and
cross-country paths, while using both one and two packet capture
hosts. In most cases, nettimer has an error of less than
10%, but at worst has an error of 40%, even on cross-country paths
of 17 or more hops. It converges within 10KB of the first large packet
arrival while consuming less than 7% of the network traffic being
measured.
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