P4P Remodels File Sharing

Peer-to-peer routing technology being tested by Internet service providers could change networking.

"Peer-to-peer" (P2P) is synonymous with piracy and bandwidth hogging on the Internet. But now, Internet service providers and content companies are taking advantage of technology designed to speed the delivery of content through P2P networks. Meanwhile, standards bodies are working to codify the technology into the Internet's basic protocols.

Credit: Technology Review

Rather than sending files to users from a central server, P2P file-sharing networks distribute pieces of a file among thousands of computers and help users find and download this data directly from one another. This is a highly efficient way to distribute data, resistant to the bottlenecks that can plague centralized distribution systems, but it uses large amounts of bandwidth. Even as P2P traffic slowly declines as a percentage of overall Internet traffic, it is still growing in volume. In June, Cisco estimated that P2P file-sharing networks transferred 3.3 exabytes (or 3.3 billion trillion bytes) of data per month.

While a PhD student at Yale University in 2006, Haiyong Xie came up with the idea of "provider portal for peer-to-peer," or P4P, as a way to ease the strain placed on networking companies by P2P. This system reduces file-trading traffic by having ISPs share specially encoded information about their networks with peer-to-peer "trackers"--servers that are used to locate files for downloading. Trackers can then make file sharing more efficient by preferentially connecting computers that are closer and reducing the amount of data shared between different ISPs.

During its meetings last week in Japan, the Internet Engineering Task Force, which develops Internet standards, continued work on building P4P into standard Internet protocols. However, Xie believes that those efforts will take two or three more years to come to fruition. In the meantime, he says, many P2P application makers and Internet carriers are already implementing their own versions of P4P.

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Pando Networks, which facilitates Internet content delivery, was the first company to adopt P4P techniques. In collaboration with Xie, Pando worked with Verizon, Telefónica, AT&T, and Comcast to run two sets of P4P tests last year; the results showed that P4P could speed up download times for file sharers by 30 percent to 100 percent, while also reducing the bandwidth costs for ISPs. Since then, Verizon and Telefónica have both implemented versions of P4P within their networks, though the network maps may not be available in all regions or to every P2P provider. Several other ISPs are considering implementing P4P, Xie says; Comcast, for instance, publicly stated its interest in the technology following last fall's trial.

Robert Levitan, Pando's CEO, says that the company used the expertise it gained through those trials to develop algorithms that automatically derive network maps, based on information gathered from software installed on individual users' machines (more than 30 million computers have Pando's media booster software installed). The company uses the maps to help route content more quickly to those same computers. The company's clients include Nexon America, one of the largest free-to-play online video-game companies, and NBC.com, which uses P4P to deliver full-length HD shows over the Internet.