BitTyrant makes a turbulent entry into digital filesharing

Jan 05, 2007

As you read this sentence, an estimated 5 million people are using BitTorrent to download their favorite movies or TV shows. The free software has achieved almost iconic status since its 2001 release, its creator profiled in glossy magazines, its users coining a new lexicon. The percentage of North American Internet traffic devoted to BitTorrent is in the double digits.

This week University of Washington computer scientists released free software that tweaks BitTorrent's cooperative core. The UW program, named BitTyrant, maximizes individual benefit by choosing file-sharing partners strategically. In doing so, it boosts downloading speeds by an average of 70 percent.

"Prior to this work, people thought BitTorrent was exactly how you want to build a peer-to-peer distributed system," said Tom Anderson, professor of computer science and engineering. "We figured out that it's easy for someone to cheat other users on BitTorrent, and we developed a set of changes that makes it much more difficult to do that."

Anderson's group began studying BitTorrent as an example of a system that uses incentives to promote cooperation. Then they went one step further, writing a program that questions BitTorrent's resistance to cheaters while improving performance. BitTyrant sparked immediate interest from the technical community, attracting more than 60,000 Web visitors on its first day.

"I hadn't expected it to blow up quite so quickly," Anderson said.

Anderson's goal isn't necessarily to help teenagers share bootlegged videos more efficiently. But BitTorrent is popular because it excels at sharing mammoth files over the Internet. Earlier versions of file-sharing, such as Kazaa and Napster, simply allowed people to trade files. BitTorrent chews up each file into a series of pieces, downloads each one separately and then stitches the pieces back together. Groups of users download files from one another, rather than a central server. A computer can be downloading a chunk of the latest episode of "The Sopranos" from one computer while simultaneously uploading another chunk to someone else.

Start-up companies are eager to develop a more reliable version of BitTorrent that can deliver high-definition television content over the Web, for instance, or distribute software releases, Anderson said. Even BitTorrent has gone legit -- creator Bram Cohen signed a multimillion-dollar contract last year to deliver content for major film studios.

"Peer-to-peer traffic is by far the largest form of traffic on the Internet today. It doesn't show any signs of dissipating," said Michael Piatek, a UW doctoral student. "Incentives are a crucial factor. Even the Internet itself can be thought of as a loosely federated group of individual organizations," he added. "How to coordinate the competing interests of these many players efficiently is an open question."

BitTyrant boosts an individual's download speed while fixing a bug in BitTorrent. Instead of choosing download partners at random, BitTyrant looks for computers that are contributing a lot of content. Choosing high-bandwidth partners boosts the individual's payoff. It also punishes people who have managed to use BitTorrent without sharing any content. So the update helps the individual, while leaving cheaters in the cold.

Philosophers have long lamented the "tragedy of the commons." This first referred to a group of shepherds who share a grazing pasture. When a single herder inflates the size of his herd he gains a huge benefit, but if everybody does it the shared pasture turns bare and everybody loses. More generally, when people act purely in their own interest they can destroy shared resources, and this ultimately harms each individual. It turns out the concept applies equally well to computer users in the twenty-first century.

For the researchers, "studying networks and file-sharing is really a way to get a picture of how we design systems that incorporate the motivations of the people using them," said Piatek. He will present a paper on the file-sharing technology at the Networked Systems Design and Implementation meeting in Cambridge, Mass., in April.

Meanwhile, the file-sharing world may be in for a jolt. An estimated 80 million people have a copy of the BitTorrent software. Many of them may be about to make an upgrade.

The research is funded by the National Science Foundation and the Achievement Rewards for College Scientists Foundation.

For a free copy of BitTyrant and for more information, go to bittyrant.cs.washington.edu/

Source: University of Washington

Explore further: Researcher develops method for monitoring whether private information is sufficiently protected

add to favorites email to friend print save as pdf

Related Stories

When things get glassy, molecules go fractal

1 hour ago

Colorful church windows, beads on a necklace and many of our favorite plastics share something in common—they all belong to a state of matter known as glasses. School children learn the difference between ...

FCC to propose pay-for-priority Internet standards

1 hour ago

The Federal Communications Commission is set to propose new open Internet rules that would allow content companies to pay for faster delivery over the so-called "last mile" connection to people's homes.

SK Hynix posts Q1 surge in net profit

1 hour ago

South Korea's SK Hynix Inc said Thursday its first-quarter net profit surged nearly 350 percent from the previous year on a spike in sales of PC memory chips.

Brazil enacts Internet 'Bill of Rights'

1 hour ago

Brazil's president signed into law on Wednesday a "Bill of Rights" for the digital age that aims to protect online privacy and promote the Internet as a public utility by barring telecommunications companies ...

Recommended for you

Tackling urban problems with Big Data

7 hours ago

Paul Waddell, a city planning professor at the University of California, Berkeley, with a penchant for conducting research with what he calls his "big urban data," is putting his work to a real-world test ...

Computer-assisted accelerator design

Apr 22, 2014

Stephen Brooks uses his own custom software tool to fire electron beams into a virtual model of proposed accelerator designs for eRHIC. The goal: Keep the cost down and be sure the beams will circulate in ...

User comments : 0

More news stories

Facebook buys fitness app Moves

Facebook has bought the fitness app Moves, which helps users monitor daily physical activity and their calorie counts on a smartphone.

Autism Genome Project delivers genetic discovery

A new study from investigators with the Autism Genome Project, the world's largest research project on identifying genes associated with risk for autism, has found that the comprehensive use of copy number variant (CNV) genetic ...

Study links California drought to global warming

While researchers have sometimes connected weather extremes to man-made global warming, usually it is not done in real time. Now a study is asserting a link between climate change and both the intensifying California drought ...