Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carnegie Mellon P2P system promises faster music, movie downloads

12.04.2007
Technique uses similar data files, not just identical files, as sources

A Carnegie Mellon University computer scientist says transferring large data files, such as movies and music, over the Internet could be sped up significantly if peer-to-peer (P2P) file-sharing services were configured to share not only identical files, but also similar files.

David G. Andersen, assistant professor of computer science at Carnegie Mellon, and Michael Kaminsky of Intel Research Pittsburgh have designed such a system, called Similarity-Enhanced Transfer (SET). By identifying relevant chunks of files similar to a desired file, SET greatly increases the number of potential sources for downloads. And boosting the number of sources usually translates into faster P2P downloads, Andersen explains. How much SET could speed up downloads varies based on a number of factors, including the size and popularity of a given file. In some cases, SET might speed transfers by just 5 percent; in others, it might make downloads five times faster.

The researchers, along with graduate student Himabindu Pucha of Purdue University, will present a paper describing SET and release the system code at the 4th Symposium on Networked Systems Design and Implementation, April 11 in Cambridge, Mass.

"This is a technique that I would like people to steal," Andersen said. Though he and his colleagues hope to implement SET in a service for sharing software or academic papers, they have no intention of applying it themselves to movie- or music-sharing services. "But it would make P2P transfers faster and more efficient," he added, "and developers should just take the idea and use it in their own systems."

"In some sense, the promise of P2P has been greater than the reality," Andersen said. By creating many more sources for data files, P2P reduces bottlenecks for data transfers. But residential Internet service providers allot far more bandwidth for downloading than they do for uploading files, an imbalance that continues to slow P2P data transfers. And members of P2P services often limit their computer's upload capacity so it is not tied up with other peoples' uploads.

Like P2P services such as BitTorrent, Gnutella and ChunkCast, SET speeds up data transfers by simultaneously downloading different chunks of a desired data file from multiple sources, rather than downloading an entire file from one slow source. Even then, downloads can be slow because these networks can't find enough sources to use all of a receiver's download bandwidth. That's why SET takes the additional step of identifying files that are similar to the desired file.

No one knows the degree of similarity between data files stored in computers around the world, but analyses suggest the types of files most commonly shared are likely to contain a number of similar elements. Many music files, for instance, may differ only in the artist-and-title headers, but are otherwise 99 percent similar.

Different versions of software packages likewise remain highly similar.

Taking advantage of those similarities could speed downloads considerably. If a U.S. computer user wanted to download a German-language version of a popular movie, for instance, existing systems would probably download most of the movie from sources in Germany. But if the user could download from similar files, the user could retrieve most of the video from English versions readily available from U.S. sources, and download only the audio portion of the movie from the German sources.

SET's basic operation is similar to that of BitTorrent. Once the download of a data file is initiated, the source file is divided into smaller, unique chunks — SET divides a one-gigabyte file into 64,000 16-kilobyte chunks, for instance. Different chunks are downloaded simultaneously from numerous sources that have the identical file, and then the chunks are reassembled into a single file.

But while that process of downloading is under way, SET continues to search for similar files using a process called handprinting, inspired by techniques that have been used for clustering search results or detecting spam. A sampling technique is used to see if non-identical files contain chunks matching those of the desired file. Relevant chunks can then be downloaded from the similar files identified by this method.

In tests based upon real files downloaded from today's peer-to-peer networks, SET improved the transfer time of an MP3 music file by 71 percent. A larger 55-megabyte movie trailer went 30 percent faster using the researchers' techniques to draw from movie trailers that were 47 percent similar. The researchers hope that the efficiency gains from SET will enable the next generation of high-speed online multimedia delivery.

Byron Spice | EurekAlert!
Further information:
http://www.cmu.edu

More articles from Communications Media:

nachricht High Number of Science Enthusiasts in Switzerland
05.02.2018 | Universität Zürich

nachricht Between filter bubbles, uneven visibility and transnationality
06.12.2017 | Schweizerischer Nationalfonds SNF

All articles from Communications Media >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>