EFF Releases Tool For Testing ISP Interference

Placid notes that the EFF has announced Switzerland, a tool for testing if your ISP is interfering with your Net connection (e.g. by resetting BitTorrent transfers). It's command-line only at this point. Of course the tool is FOSS, and you can contribute to it via its SourceForge project. From the announcement: "Developed by the Electronic Frontier Foundation, Switzerland is an open source software tool for testing the integrity of data communications over networks, ISPs, and firewalls. It will spot IP packets which are forged or modified between clients, inform you, and give you copies of the modified packets."

Re:Warning to non-tech people

[retroStick]

But it's from the Electronic Frontier Foundation! If you can't trust them to be non-evil, who can you trust?

Behavior is as important as bandwidth

[Brett Glass]

OK, this is somewhat of a network techie/geeky thing, but you can hog the network even if your bandwidth is capped. This is due to a flaw in TCP, which does very weak, per-flow congestion avoidance. Suppose one user is running a single download at X bits per second. A second has 100 streams going, each with 1/100th of the bandwidth (or X/100). Which one gets priority if the network gets congested? The second -- by a factor of 100! BitTorrent, which is used for downloads that are not time critical, seizes priority over other traffic such as VoIP, which really needs real time performance. What's more, the streams for which it seizes priority use large packets because they are downloads. The large packets, in turn, create jitter, which really messes up VoIP. The same is true for gaming. So, ISPs are doing the right thing when they throttle BitTorrent and keep it from opening up too many streams. And if they recognize that the thing that's hogging the bandwidth is BitTorrent, they can do so gracefully. They can undo the attempt to seize priority and mete out the bandwidth appropriately. If they are forced to be "protocol agnostic" (the word "agnostic" means "without knowledge;" in other words, their bandwidth limiter is not able to recognize exactly what's causing the problem), they can't use a strategy that's carefully tailored to the problem. So, the networking management can't be as good, and all users suffer. That's what the Sandvine appliance does. It "prunes" the number of streams started by BitTorrent down to a manageable level. It doesn't stop it altogether, but it keeps it from interfering with others by exploiting a vulnerability in the protocol.