I am trying to figure out how to scientifically check and prove if my connection is being throttled by my Internet provider. Last time I asked them about this issue, they denied throttling and blamed the Web servers and congested international backbones.

Of course, I don't buy their excuse because I see a pattern: I get low bandwidth no matter which server I'm pulling contents from at between 5:00 PM to 01:30 AM and I'm not their only customer holding this suspicion.

The throttling (if true) is ridiculous: I only get < 2 Mbps on 12 Mbps ADSL, with occasional short bursts up to 8 or so Mbps, at aforementioned times. I need this information to help me decide to stick with them or swing to a different provider.

So, what can I do to precisely tell whether my connection is being throttled?

  • 3
    Sounds like the time everyone is using Netflix to stream movies. – Moab Jun 13 '11 at 21:41
  • If other providers in your area offer trial periods, you can always test them out. Some providers are just better than others. – Keltari May 23 '13 at 0:33
  • There is no difference between throttling and congested backbones/interconnects. Why do you think an ISP throttles people? It doesn't cost them more money to carry more bits on the same pipes. – David Schwartz Jan 3 '17 at 12:34

Unless you have access to their equipment, you can't. All you can really do is document your throughput over a reasonable length of time, like a week, and collect statements from other users.

I don't think you necessarily have a case, however. Since during off-peak times your connection performs as it should, you can assume that there's no technical issue with the line itself and that your ISP is in fact providing you with the connection you signed up for.

Note that when you buy a particular speed connection from a service provider, that speed only pertains to the line between your location and the ISPs border router; your ISP has no control whatsoever what happens to packets once they're out on the internet.

Therefore, what you're describing does sound like latency to me. Your issues happen during peak hours, when most of your ISPs other customers are using their internet connections simultaneously.

However, depending on the type of "downloading" you're doing, your traffic might be getting lower priority causing your throughput to appear to be slowing down. In that case, what you're calling "throttling" is actually called packet shaping.

ISPs have every right to limit, for instance, P2P traffic on their networks, because otherwise it can literally cripple a network. There's no way an ISP can allow all its users to have full bandwidth on any protocol they desire, because then a very few would make decisions that would result in not just latency but downright outages affecting hundreds or thousands, and no service provider can afford to tolerate that.

If you want a circuit that gives you unrestricted access to all protocol types at all times, you will need to pony up some real money and lease a private line directly from a CLEC. It could cost hundreds or even thousands per month, but there'd be no packet shaping and you wouldn't have to share.




Go here, run a speed test, then it will tell you what you're getting on the up and down (it's kinda like a ping, just telling you how fast the signal is traveling). If it's near the up/down you're suppose to get from the provider, it's fine. If it's not near the up/down, either your computer is bunk (you can test the ping with another laptop); or you need to call your provider because something is causing bad signal.

  • Actually speedtest isn't much use if it comes to testing to see if your connection is being throttled. Typically the ISP will throttle after you've transferred a certain amount of data. So for instance my torrents will start off downloading at 5mb/s then after a min or two will get throttled to 2mb/s – user226194 May 23 '13 at 0:26
  • Quite, though repeated speed tests may reveal a pattern. Though they can always just throttle torrent traffic, which means the test will look fine even though the torrent is slow. – zeel Oct 21 '13 at 18:22

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