Screwy router action

[Spiffy McBang]

I have a roommate. She likes to torrent. When she does this, my internet connection essentially goes kaput. I can't connect to anything I'm not already connected to; that is to say, I can't load any websites, nor join any online games, but if I'm already in an online game I'm able to stay on with no issues.

This may seem like a "duh" kind of problem, but it gets stranger, and we're both at a loss to explain it: My internet connection remains in this purgatorial state any time she has uTorrent running... even if there are no active torrents. I don't mean that her listed torrents have no action on them, I mean that the queue is empty. She's not actually torrenting anything, but it fubars my connection as badly as if she were trying to download the entire internet at once. (FWIW, we have tried capping both upload and download, to no effect.)

As far as I can tell, when I torrent it doesn't affect her the same way, but it's rare I do that so we don't have any sort of scientific sample to work with. We use a four port Netgear router (wireless, but we're both wired in), and I've swapped around the ports each of us are in to no effect. We're out of ideas. Help.

[Blinding]

There are two resources you need to be concerned with. One is the bandwidth and you seem aware of that.

The other important resource is the number of connections. The router, running NAT, needs to keep track of each active connection. This includes both TCP and UDP connections. Internally it has a table containing IP and port numbers for every connection. It requires this so when data comes in it knows what system to send it to.

Home routers typically only support a few hundred connections. The exact number is not documented. They don't expect a couple of people browsing the web to use very many connections so they don't make the tables very big.

Utorrent has configuration options that control how many total connections can be used and how many for each torrent. I suggest severely limiting those and see if it helps. Start with 100 connections total. If that works you can try more and see where it fails.

There is alternate firmware you can download that will allow more connections. Check out http://www.polarcloud.com/tomato and see if they support your model. It is pretty much the same as upgrading the router firmware except with their improved version.

[Spiffy McBang]

No dice. :\ Kicked it down to 50 connections, which dropped her DL speed to an unusable 5k/sec, and it still left me without internet access. Our wireless is secure as can be, so I don't think that's it. Our router isn't listed on that site, either.

Good ideas, but the problem remains.