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P2P drag on nets getting worse

By , Network World
August 02, 2004 12:09 AM ET

Network World - Peer-to-peer traffic has reached an all-time high across the Internet, bringing with it heightened security and legal threats for companies that fail to rid their networks of these popular applications.


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For years network managers have been playing a cat-and-mouse game as they try to block employees from using peer-to-peer Web sites that let visitors share copyrighted or illegal material. Now the stakes are getting higher.

Nearly 40% of Internet users admitted to downloading and sharing files through peer-to-peer sites while logged on to corporate networks, according to a survey that security vendor Blue Coat Systems conducted in March.

ISPs report that peer-to-peer traffic represents anywhere from 30% to 70% of their overall traffic, depending on whether their networks reside at the core or the edges of the Internet.

"We tell corporate users that they should be disallowing peer-to-peer traffic on their networks,'' says Lydia Leong, principal analyst with Gartner. "We believe strongly that it places companies at risk, and it is potentially a security issue and a bandwidth constraint.''

LexisNexis uses a multilayered approach to prevent its 9,000 U.S. employees from downloading copyrighted materials such as music, videos or software via peer-to-peer. John Mawhirter, a consulting telecommunications engineer with LexisNexis, says the legal information provider has used Websense Enterprise Web-filtering software for five years, and last year added a Web-caching appliance from Blue Coat for extra protection.

"We also use firewalls to shut down the ports for music and video,'' Mawhirter says. "And we have a software product that scans all the company computers to make sure no one has installed software that they shouldn't.''

Mawhirter says this combination works well and has prevented LexisNexis from running into legal, security or productivity problems. He says the Websense software is flexible enough to allow for different rules in terms of blocking pornographic Web content in the U.S. and Europe, which have different views of what is inappropriate.

"There are different standards in Europe, so our European employees are not blocked under Websense,'' Mawhirter says. "Our legal and [human resources] people aren't under Websense either, but the IT department is.''

ISP issues

The workplace isn't the only trouble spot. ISPs that offer broadband residential services say peer-to-peer traffic represents two-thirds or more of their upstream traffic, although some say that isn't necessarily a bad thing.

Peer-to-peer traffic is especially high in Europe, where file swapping is more popular than it is in the U.S.

"Peer-to-peer traffic is a big problem for the ISPs,'' says Andrew Parker, founder and CTO of CacheLogic, which sells switches and servers that let ISPs separate and cache peer-to-peer traffic to improve the performance of their networks. "As much as 80% to 90% of upstream traffic on the last mile is peer-to-peer.''

CacheLogic says that when it was conducting a field trial for a Tier 1 European ISP, it found peer-to-peer traffic volumes were at least double and sometimes 10 times higher than that of other Web traffic during peak evening hours.

Top-tier ISPs in the U.S. report less peer-to-peer traffic because they carry more business-oriented traffic.

Peer-to-peer traffic is "certainly less than half" of AT&T's overall IP traffic, says Craig Uthe, AT&T's IP network product management director. "Web traffic is clearly the biggest portion of our IP traffic.''

Sprint says 21% of its overall traffic is identifiable peer-to-peer traffic. In addition, peer-to-peer sites account for some of Sprint's Web and TCP traffic, which together represent 60% of its overall traffic.

"Peer-to-peer is clearly a large amount of our traffic,'' says Chase Cotton, director of data engineering for Sprint. "Our network is designed to carry those packets, and someone is paying for them to be carried. So for me it doesn't matter what the traffic is being used for.''

As ISPs struggle with managing the deluge of peer-to-peer traffic, start-ups such as CacheLogic, P-Cube and Sandvine offer products that help analyze their traffic so they can segment and support peer-to-peer applications more cost-effectively.

Peer-to-peer traffic is hard to measure because it is very dynamic. Popular peer-to-peer sites such as BitTorrenteDonkey and FastTrack use dynamic ports, hashes, tunneling and other tricks so traffic appears to be something other than peer-to-peer file swapping.

"Peer-to-peer is a difficult problem for corporate network managers to deal with because it masquerades as something else,'' Parker says. "The peer-to-peer clients are very sophisticated, and they work hard to circumvent [firewalls, proxies and other perimeter defenses]. You have to look deep into the traffic. . . . It's not a simple job for network managers to block these applications.''

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