Peer-to-peer file sharing, the primary vehicle for online piracy, has been as unpopular with Internet service providers as it has been popular with users.
Providers have banned, blocked or slowed peer-to-peer traffic in their efforts to keep the flood of music, video, games and software from overwhelming their networks.
But Verizon Communications Inc. has broken ranks with the industry and is set to announce Friday that it plans to help its users share files faster — at least those who do it legally.
With researchers at Yale University and a group of companies that make file-sharing software, Verizon collaborated to enable faster downloads for consumers and lower costs for participating ISPs.
File-sharing accounts for one-third of all Internet traffic, according to Arbor Networks, a maker of traffic-management equipment, and some estimates are higher.
At a conference in New York, the Verizon group will present test results showing that when an ISP cooperates with a file-sharing software maker they can speed downloads an average of 60 percent — though collaboration boosted some downloads six-fold on fast Internet connections.
"This test signifies a turning point in the history of peer-to-peer technology and ISPs," said Robert Levitan, chief executive of file-sharing company Pando Networks Inc. "It will definitely show ISPs that the problem is not peer-to-peer technology, the problem is how you deploy it. It is possible to deploy P2P to their advantage."
In P2P systems, users download files from one another, usually at the same time they're uploading files to other users.
[The original Napster was a P2P system, although it used centralized servers to index files made available by users and to coordinate uploads and downloads.
After Napster was shut down in 2000 by a record-company lawsuit, networks using decentralized P2P software became the norm, such as the currently used Limewire, Gnutella and KaZaA networks.
Using them, each downloader and uploader makes individual, one-on-one connections, removing the need for a middleman such as Napster. But such file transfers are limited by the speed of each user's connection to the Internet.
A further refinement came with BitTorrent software, which got around speed limitations by distributing uploads among many different users — a one-on-many protocol.
Because dozens or hundreds of uploaders will have identical copies of the same song or video clip, the software takes only small bits of the original file from each one and then reassembles the complete file on the downloader's computer.
The dramatic speed of BitTorrent "clients" meant that full-length movie downloads finally became manageable around 2002, forcing the movie industry to confront the same problem the music industry had with Napster.]
One of the problems for ISPs has been that file-sharing networks connect users more or less at random around the globe — so a U.S. file-sharer may simultaneously download files from Greece and Japan and upload to users in Belgium and Argentina.
This long-distance carriage is expensive for ISPs.
Verizon shared details about the structure of its network with the researchers and Pando in the "P4P Working Group," created last summer, and they together created a system that connected users not randomly, but to other users close by.
In a traditional P2P network, if a Verizon customer downloads a file, only 6.3 percent of the data will come from another Verizon customer in the same city, said Doug Pasko, senior technologist at the company.
In the "P4P" trial, 58 percent of the data came from nearby Verizon users, vastly reducing the company's cost of carrying the traffic.
Levitan said the technology might be ready for use by next month, when NBC makes available free downloads of its TV shows using Pando's software.
The shows will be financed by advertising, and P2P technology will be an essential way for NBC to cut costs.
Distributing an hourlong TV show in high definition using traditional delivery systems would cost the network about $1. With P2P technology, that cost can be cut by 75 to 90 percent.
"The Internet is quickly transforming into a media distribution platform, and there are people who say: 'It will break. It's not built to move music and movies and games and software,'" said Levitan. "New technologies are needed, and this is one of those technologies."
For other ISPs to reap the benefits Verizon did in the test, they too would have to share information about their networks with file-sharing companies, and that they normally keep that information close to their chests.
"That's one of the objectives we have to solve — how are we going to consolidate this data and distribute it?" Pasko said, adding that the results of the test gives ISPs plenty of incentive to collaborate.
A problem the "P4P" system does not address is that file-sharing software makes extensive use of a customer's connection, both for uploads and downloads.
This is not much a problem for phone companies like Verizon, but it is for cable companies, where up to 500 households share capacity on the local coaxial cable.
Cable companies have been the toughest on P2P file-sharing.
Comcast Corp., the country's largest cable company, is being investigated by the Federal Communications Commission for secretly placing temporary roadblocks in the way of file-sharing traffic.
Other cable companies admit to using less drastic methods to slow file-sharing and keep it from drowning out other forms of traffic.
AT&T Inc. also has sounded the alarm on file-sharing, saying it is looking at ways to block its customers from sharing and downloading pirated content, an approach Verizon rejects.
"Verizon does not accept the role of network police agency," the company said.
Pasko stressed, however, that Verizon wants to work with P2P companies that are focusing on delivery of legitimate media, like Pando — not systems where anyone can upload anything, which usually means lots of pirated material.
Verizon's acceptance of peer-to-peer traffic also doesn't extend to its wireless networks: it bans the technology for users of its laptop cards.
Much like cable modem users, wireless users share download capacity with others in the neighborhood.