How to Test for Bandwidth Limiting by Your ISP

Doing some downloading or uploading on your "high-speed" internet connection and notice that the speed seems to drop off? Bandwidth is a measure of the speed of data transmission over a network or the internet (often represented in Kbit/s or Mbit/s). Bandwidth throttling happens when any server attempts to limit the amount of bandwidth that a given service may use. The common example is Internet Service Providers limiting the bandwidth usage of common BitTorrent clients on their network.^[1] Let's examine how you can tell if your internet service provider is throttling your speed.

Measurement Lab Method (Windows)

Google recently released M-Lab which is a multi-functional internet performance measurement tool.

1. Visit http://www.measurementlab.net/.
2. Open the test selector by clicking "Test Your Internet Connection".
3. Select one of the available tests.
   
   
   • Network Diagnostic Tool: tests speed and looks for common issues that can cause a slow down.
   • Glasnost: tests to see if BitTorrent specifically is being throttled.
   • Network Path and Application Diagnosis: similar to the Network Diagnostic Tool with a smaller ranger of search functions. ("Last mile connection issues")
   • DiffProbe (Coming Soon): will test to see if your ISP is using different priorities for different types of traffic.
   • NANO (Coming Soon): used to determine if your ISP is placing limits on only some users and not others.
4. Follow the on-screen instructions to complete each individual test. (Please note: some of the tests are hosted on third party websites.)

Switzerland Method (Mac / Windows / Unix / Linux)

Switzerland is an open source application created by the Electronic Frontier Foundation, named as such because it promotes Net-Neutrality.

1. Visit http://www.eff.org/testyourisp/switzerland to read about the project.
2. Download the software from Source Forge
   
   
   1. Click on the latest release.
   2. Select the file format you would like to download. (Either .zip or .tgz)
3. Extract the files from the zip or tgz archive and follow the instructions contained within the INSTALL.txt file specific to your platform.

Tips

• There are other more complicated methods of testing for bandwidth throttling that may provide greater insight into exactly what is happening for the technically savvy. A quick search of your favorite search engine for "Bandwidth Throttling" should get you on your way to discovering them.
• If this is something that you are passionate about, you may consider joining one of the various Net-Neutrality groups around the internet. Again, a quick search of your favorite search engine for "Net Neutrality" will return some great resources and groups to help you get involved in fighting things like ISP Throttling.

Warnings

• Some internet service providers may be able to detect the nature of the test site and provide false results by boosting the speed to the test site. Use a number of different tests for the most accurate reading possible.