Pathload2 was decommissioned on 12/21/2012. The source code and the data are still available at the links provided below.
Pathload2 determined the available bandwidth of an Internet connection, in both upstream and downstream directions. Unlike many other speed tests, Pathload2 used active probing methodologies to estimate available bandwidth in a way that did not depend on a specific protocol or application. The available bandwidth is the maximum bit rate that can be sent to a network link before it gets congested.
Please cite this data set as follows: The M-Lab Pathload2 Data Set, <date range used>. http://measurementlab.net/tools/pathload2
Data collected by Pathload2 is available in raw format at https://console.cloud.google.com/storage/browser/m-lab/pathload2.
Source code and more information is available at https://code.google.com/p/pathload2-gatech/.