Over the past few weeks I’ve noticed a weird “throttling” effect on my Internet traffic. I’m on Qwest’s “Fastest” home DSL, and after I start up my BitTorrent downloading and uploading, it fluctuates. Every once in a while it will rapidly descend to 0 kb/s, and the connection goes dead, essentially. I can’t download, upload, surf the web, ping servers, and so on.

Then, after around 5 seconds or so, it ascends back to normal, and I can download and access the Internet once again. Until, of course, this whole process repeats itself. It’s getting quite annoying, and I did a bit of Google research, coming up with a forum thread on which ISPs throttle BitTorrent traffic. The last one caught my eye:

Despite what the website says, Qwest doesn’t block P2P traffic. People have had problems with the modem locking up due to too many connections and the like leading them to believe that Qwest is throttling them. This issue has come up multiple times on the Qwest forum.

Every connection generates errors; moreso if you have a long line with high attenuation. Interleaving trades latency for stability. Some don’t like it, but the policy has nothing to do with laziness. #

I don’t know what to do about this, however. It seems rather surprising that a modem would cave under minor BitTorrent traffic (around 30 kb/s altogether) and if it does, the next thing I may try is to use another modem to dial up to the Qwest DSL, since all it uses is PPPoA.


  • I’d say giving another modem a try would probably be a good idea. It’s fairly simple to do, and it may very likely solve your problem. If you’re using a separate router, I’d also try swapping it out (probably try it first), since it has more overhead than the modem does.

    I’ve found that a lot (and I mean LOT) of the cheaper hardware out there (modems, routers, etc.) all suffer from similar problems. They skimp on one thing or another to cut costs, and most of the time everything works out alright. For 99% of users, they probably wouldn’t ever have a problem.

    It’s those who hit this crappy hardware with 100 simultaneous connections (regardless of their transfer rate) that can run into problems. Poorly-written networking stacks, lack of sufficient memory to manage those stacks, etc. can all crap out, requiring that everything be purged (I generally have to power cycle my router) and start fresh… Then you essentially rinse and repeat the process until your download finally finishes.

    If they were throttling your connection at the ISP level, I wouldn’t expect it to 1) kill all your traffic, or 2) magically restore itself x seconds later. Sounds a lot like the modem or router is getting too many connections to simultaneously keep track of and flipping out. After it resets whatever it is it needs to clear out, everything pops right back up and you go about your business.

  • Thanks for the advice. I was pretty sure it wasn’t the ISP throttling, as the fluctuations wouldn’t really make sense, but maybe Qwest is weird in some way?

    My plan is to go to a Best Buy or Circuit City or whatever and get a half-decent modem, then try that. Buying it in a real store rather than an online store such as Newegg gives me the opportunity to easily return the modem if it doesn’t solve things :).

  • Hey there,

    I found your site from a Google search, and I am having what appears to be the same problem with my Qwest DSL. I also have Qwest’s ‘fastest’ DSL, though they connected me up to the 5 mbps line instead of the 7 mbps one because they said that there were errors on the line when running at 7 (but of course charged me the same and told me I ‘probably wouldn’t be able to tell the difference’ — great).

    Anyhow, I am thinking about trying a new modem as well. I’d be interested in hearing about any updates to this, and I’ll post a comment if I find anything that works to fix it, too.

    Best of luck! Ben in Seattle

  • I actually isolated it down to the wireless — if I hook it up to the Ethernet via a hardwire, the problem goes away and I can download for hours on end without any problems. So either it’s the wireless part of the modem which is pretty crappy, or the AirPort card in my laptop which is failing. I don’t think it’s the AirPort card, so I’m going to try hooking up a wireless router I have from previous setups to the Qwest modem and hopefully that will take care of it.

    Are you connecting via wireless or Ethernet? If you’re using wireless I’d recommend trying out hardwire. Might fix the connection problems but I must say convenience does not come with that ;).

  • It most likely is your wireless. I have used about twenty different routers with three laptops, and each of them drops the connection under a heavy load such as Downloadthemall or bittorrent.

  • I recently purchased a new “2 wire” qwest wireless modem. Prior to this purchase, I was able to view streamed netflix movies with no problems on my home computer. With the new modem, I am virtually unable to view the whole movie without it telling me I am having internet problems. When I stay at a hotel with a good wireless connection, I have no problems at all viewing netflix movies. At home though I am hardwired and even the regular web page at netflix has problems loading. I am wondering if it could be the modem as you all have described here except that it isn’t Bit Torrent but is netflix.

    Any suggestions?

  • Hey Robin, what your experiencing is your router crapping out due to too many incoming/outgoing TCP connections. It’s not because of the speed at which you are downloading (hence why it still happens when you’re only downloading at like 30k).

    The most immediate solution is to simply put a cap on how many TCP connections your bit torrent client will allow. Most clients have an option for this in their preferences. Right now I have mine set to 200 max connections. I used to experience the same thing as you but it’s working fine now. The only downside is that since you are connecting to less peers/seeds there is a chance that on some torrents you might not be able to download as fast.

    The best solution is to just buy a router that can handle a high number of TCP connections. The DSL modem/routers that Qwest provides all seem to have problems with this, so it’s best if you just put your modem into transparent bridge mode and then add another router into the mix for routing traffic. Hope that helps.

  • @Kevin Davies: That definitely makes sense. I’ve been toying around with buying a 3rd party modem (from Newegg or something) that I know doesn’t suck but I wasn’t sure if that was the problem. It’s very nice to know that it’s just the modem, and not the connection itself.


  • Yes, if someone could recommend a good 3rd party modem that’s verified to work with Qwest DSL and won’t buckle under these conditions, please let us know! Thanks!

  • or alternatively, how many connections are qwest modems able to handle? you could always change your bittorrent settings to avoid exceeding the max.