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.

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.)

source: www.wikihow.com