Cooperative Distribution: How To Distribute Large Media Files Via BitTorrent
I know this is no breaking news for many of you as BitTorrent has been making the headlines for just about two years now, but I keep receiving many requests of professionals wanting to know more about this revolutionary P2P protocol and its unique benefits for distributing VERY LARGE files on the Internet.
Photo credit: Luis Alves
I present here two complementary points of view, that should give you a good, synthetic and not technical overview of what BitTorrent is and why you may want to look closer into it.
"BitTorrent gives you the same freedom to publish previously enjoyed by only a select few with special equipment and lots of money. ("Freedom of the press is limited to those who own one" -- journalist A.J. Liebling.)
You have something terrific to publish -- a large music or video file, software, a game or anything else that many people would like to have. But the more popular your file becomes, the more you are punished by soaring bandwidth costs. If your file becomes phenomenally successful and a flash crowd of hundreds or thousands try to get it at once, your server simply crashes and no one gets it.
There is a solution to this vicious cycle."
"BitTorrent, the result of over two years of intensive development, is a simple and free software product that addresses all of these problems.
The key to scaleable and robust distribution is cooperation. With BitTorrent, those who get your file tap into their upload capacity to give the file to others at the same time.
Those that provide the most to others get the best treatment in return. ("Give and ye shall receive!")
Cooperative distribution can grow almost without limit, because each new participant brings not only demand, but also supply.
Instead of a vicious cycle, popularity creates a virtuous circle. And because each new participant brings new resources to the distribution, you get limitless scalability for a nearly fixed cost.
BitTorrent is not just a concept, but has an easy-to-use implementation capable of swarming downloads across unreliable networks."
(Source: BitTorrent site)
As a kid, my parents always told me, "If you share, there will be more than enough for everyone."
Bram Cohen, creator of new file-sharing software, has freshly illustrated this old adage. He spent a year building BitTorrent, which he now freely shares on the Internet.
BitTorrent allows individuals, organizations and companies to distribute large video files over the Internet without encountering unexpected obstacles.
Imagine that you've posted a 900-megabyte educational video on your website for free downloading, hoping that visitors will store your video on CD and play it in classrooms around the world. As word spreads, traffic triples and the masses stream to download the video, the server is overloaded, prompting the Internet service provider to immediately shut down your site.
Too grim a scenario?
It can get worse.
Imagine waking up to find a $10,000 bill from that web hosting company, simply passing along the costs of distributing your large video file.
But Cohen discovered how to circumvent the complications of downloading video.
A torrent file (which has a '.torrent' extension) breaks a regular file into several different parts, which means that no central server is needed. Additionally, the bandwidth needed to distribute the file is partially provided by those who are downloading it.
By using a torrent file, large video files can be distributed without the excessive server load.
In fact, the more popular a torrent becomes, the more distributed (and manageable) the file. BitTorrent harnesses the upstream bandwidth of every user downloading a torrent file, which means that he or she simultaneously retransmits the torrent.
A Personal BitTorrent Experience
On the weekend of June 19, 2004, I witnessed BitTorrent work magic. The link to a 900 megabyte video by Seattle Wireless Television was featured on the popular website Slashdot.org, which meant that as many as 10,000 people might concurrently attempt to download the video.
I quickly downloaded the small torrent file (about 50 kilobytes). A quick double-click of that small file launched BitTorrent on my iBook laptop (there are also BitTorrent programs for Windows and Linux).
My DSL service gives me a relative fast upstream (768 kbps). This means I can upload files to the Internet fairly quickly. It also means that when I use BitTorrent, I can "pass on the bits" very easily to others who are downloading the same files that I am.
I started downloading the video at midnight on Saturday. When I woke up on Sunday morning, 700 megabytes of the 900 megabyte file has been downloaded to my computer. The BitTorrent software also showed that I was peering with 37 other people, who were uploading the very same video file I was downloading to them. My upload rate was 80 kbps. Since the rate is evenly shared among those using it, each one of the 37 people receiving the video file from me had access to a rate of a little over 2 kbps.
Best of all, using BitTorrent is easy. The software automatically redistributes the video file to other users. All I had to do was to leave the BitTorrent software running until I had fully downloaded the video.
At 10 a.m. on Sunday, about 10 hours after I started the download, the video file was sitting on my hard drive. I excitedly started watching it while continuing my upload of the file to my peers. The video content was fascinating, combining geeky details with community-building in a way that made my mind giddy with delight.
Sharing the Wealth
Having downloaded such a high-quality video, I wanted to share it with others. Even though I was finished downloading the file, I was not finished donating my upstream bandwidth to the creators of that video.
I left my iBook on all day Sunday and through the night. By Monday morning, I had distributed over 6 gigabytes of data to other BitTorrent users. And they, too, were distributing the bits that they were receiving.
I can't tell you what a thrill it was to participate in the downloading and redistribution of this video file. Creating and sharing videos that celebrate community members working together towards constructive community goals is the perfect antidote to the pervasive stream of negative messages and stereotypes from mainstream media.
Thanks to BitTorrent, such videos can now be distributed at almost no cost to the creator.
Once a video has been downloaded using BitTorrent, it can also be distributed locally with speedy file duplication methods, such as connecting a laptop computer to a desktop computer using FireWire or USB 2, which can copy huge files in a few minutes.
With FireWire 800 becoming more common and FireWire 1600 on the horizon, users will soon be able to transfer one full hour of video in less than a minute. In addition, faster DSL speeds (up to 100 megabits/second within the next few years) may make BitTorrent work faster.
It appears increasingly likely that there will eventually be a single device dedicated to transferring files, which will be used alongside a computer. Though BitTorrent works well running in the background (and doesn't take up many CPU cycles), I'd prefer to keep my computer free from continuous downloads, if possible.
In an ideal future, I would subscribe to various media producers in my community (and elsewhere). Those producer's files would be automatically sent to my file transfer device, which would either be accessible from another computer on my network, or have built-in video playback capabilities.
Using BitTorrent in Your Community
There are countless ways to use BitTorrent at community technology centers (CTCs). Besides video files, the software can also be used to download open source software, massive music files, image files, and anything else you might need.
An enterprising person or organization could assemble a rich media publication that includes any combination of text, graphics, sound, animation and video. The publication could include video interviews with community members, creative expression (i.e. poetry, fiction), locally-composed music and other kinds of communication. Such a publication could then be distributed for free using BitTorrent.
A few years ago, I taught the software program HyperStudio to teachers in Virginia's Arlington Public Schools. If a tool like BitTorrent had been available, it would have been perfect for easily distributing large presentations throughout the district.
If an open source program similar to HyperStudio is ever developed, I hope that community members seize the opportunity to make compelling community media, and use this great tool to freely share their creation.
In the meantime, we can all benefit from creative uses of BitTorrent, which might just revolutionize the face of file-sharing.
BitTorrent is Free.
Original title: BitTorrent: Making Bulky Video Files Easier to Share
Digital Divide Network
by Phil Shapiro
December 10, 2004
The author is a technology access activist in the Washington DC-area.
Related Link: Windows BitTorrent/RSS software for downloading videos
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