This paper presents the design and implementation of Java-based tools for accurate bandwidth measurement for xDSL (Digital Subscriber Line) networks, including the ADSL (Asymmetric DSL) case with different upstream and downstream bandwidths. First, a multi-packet bandwidth measurement technique is presented, based on the integration of packet-pair and filtering techniques. Considering the importance of a traffic generator to accurate measurement, a smooth and stable traffic generator is studied. We also present a stepwise algorithm designed to minimize the effect of ATM traffic shaping on the bandwidth measurements in xDSL deployments. Implementation details of the components of the Java-applet- and Java-application-based tools are described. Finally, evaluation experiments in both a laboratory testbed and a commercial ADSL network demonstrate that these tools achieve accurate bandwidth measurement in xDSL networks, and offer better performance than other popular tools such as pathchar and clink in terms of accuracy and usability.
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