February 12, 2004
BitTorrent: Phase III of File Sharing


Seth Schiesel/NYTimes says Bram Cohen's BitTorrent represents the next wave for file sharing. BitTorrent is an amazing way to distribute huge files, using P2P to spread out the bandwidth across users. I tried it last summer, in an experiment to see how it worked. The process was tricky, and I don't think impatient or inexperienced users would find it easy, and the fact that it took 36 hours to download one 2 gb file was not attractive. However, it will become more attractive in the future, as people get true broadband connections, and have equal speeds moving data up and down (most home users have midband connections, where there is often double the speed downloading, as opposed to uploading, which speaks to the ways BB providers view "consumers" which is as receptacles, who therefore need mostly down speeds, where up really only for email, right? I mean, you don't think you really need to send anything else out from your system do you? If so, you must be a business user and therefore, get on a different BB plan...).

BitTorrent works by having every downloader's system simultaneously work as an uploading system (you can stop uploading when you are finished downloading, but you can't not upload while your download is in process). Since this is the case, slow uploading speeds mean your whole transfer is slower than if you were just downloading. These files are called seeders. One example of BitTorrent use might be by a software company, with webbased distribution, that wanted to make available it's programs on either a trial or free basis. Another might be a digital library or academic institution that wanted to distribute large research files or databases of information and graphics.

At the Digital Media Summit in NY the other day, Charlie Nesson, Director of the Berkman Center at Harvard, presented a system where "Interdiction" might be used as a form of self-help by content makers to disrupt the transmission of copyrighted media files. His logo was a crow (or what looked like a crow) with a long black beak, holding a seed.

This system would work to the find a middle ground between a DRM/IP regime lockdown, and what Nesson referred to as a "disaster" for the content industry, though I would argue that movies/TV/Cable are different that other media, and each media needs to be considered on it's own, when thinking about these issues. In fact, I think that low quality video files are considered to be of just-okay quality for people wanting a quick glance at content, and so they may download something on one of these networks, but that people really want the big rich high quality screen experience, hence video's inability to kill the experience or desire by people to go out to see a big screen movie, and people aalso love watching DVD's on plasma, because of the rich experience... downloaded files on little screens are just not nice in that way. Imagine watching Lord of the Rings on a five inch screen. But as bandwidth grows, it will become more of an issue, but what if these little files are loss leaders to entice people into the theaters, to buy DVD's or high quality downloads with interesting value added stuff?

The Interdiction system is designed to be a speed bump for those who would pirate, and for those who have more money than time, and would otherwise pay for their files (the system is associated with Scenario Three of the Harvard/G2 Five Scenarios for Digital Media in a post Napster world paper) . It is a form of competition for online digital media that is freely shared, so that the Interdiction would come when something is offered, and instead of a denial of service attack (another form of self-help that ties up an entire system or network, discussed by the incumbent content companies that is an illegal means for stopping filesharing), Interdiction would send a message to a seeder to take down the file and it could tie up just the seeds (not a seeder's whole system) so that no one could download. Nesson talked about a "new release" window to keep the market pristine for selling the content.

I found BitTorrent to be a really interesting system, one that could be so powerful for exchanging information, distributing files without centralization (where the distributor has to pay all the bandwidth costs, verses distributing the distribution costs as well across users), but one that needs work before the general public (those beyond the geeks) can use it.

Posted by Mary Hodder at February 12, 2004 04:42 PM

Bit Torrent clients have made a lot of progress since last summer. Azureus is pretty easy to use, and shows visually exactly how BT works. My jazzhead friends (who are mostly technophobes) use it to pull Coltrane bootlegs and the like from Sharing the Groove.

Posted by: Ryan Shaw on February 13, 2004 07:36 PM

I think your description of the interdiction is a little confusing. My understanding is that it is an actual denial of service attack against the service provider, which in this case would be the BitTorrent seeder. It's not necessarily trying to block all bandwidth to the site, but it is trying to keep the seeder from operating by swamping it with bogus requests. This is literally a denial of service attack, in that the attacker is trying to deny access to the service being offered by the seeder.

Posted by: Cypherpunk on February 14, 2004 03:25 PM

You are right that the interdiction process, at least as described in Nesson's presentation is a sort of mini-DOS attack, on just the seeder file. And the question is, how is the file verified to actually be an infringing file, and what does the actual interdiction do to the person's file, system and connection. In his talk, he did not address whether this would fall under the same rules as a system-wide DOS, but rather just mentioned that there were legal issues that would need to be worked out that were along the same lines as DOS attacks.

Posted by: mary hodder on February 15, 2004 08:01 AM

36 hours to download 2gb, last summer, is pretty good, i think.

Also, it is important to note that download speed is not strictly rate limited to upload - if a file is already well distributed, you can see download speeds max out a cable modem, with the upload at little or nothing.

A funny thing about BitTorrent is that you can request the IP of every downloader directly from the tracker, with 0 access control. Bram's spoken publically about the unsuitability of current BT implementations for the spread of contraband materials.

Posted by: dreww on February 23, 2004 04:07 PM
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