Today's deep packet inspection (DPI) products may not be adequate for large-scale detection and filtering of peer-to-peer (P2P) traffic, according to a new report by Internet Evolution.

The report, entitled "Peer-to-Peer Filters: Ready for Internet Prime Time?" sought to test P2P filtering products by emulating today's carrier networks and measuring their performance.

In a lab test commissioned by Internet Evolution and SNEP (the "Syndicat National de l'Édition Phonographique," an industry organization that represents the interest of the French music industry), the European Advanced Networking Test Center AG (EANTC) was called on to determine how well carrier-grade systems would perform under network conditions.

More than two dozen vendors were invited to participate in the test, including established players -- such as Allot Ltd. (Nasdaq: ALLT), Cisco Systems Inc. (Nasdaq: CSCO), Ellacoya Networks Inc. , F5 Networks Inc. (Nasdaq: FFIV), Huawei Technologies Co. Ltd. , Narus Inc. , Packeteer Inc. (Nasdaq: PKTR), and Sandvine Inc. -- and a number of lesser-known startups.

However, only five vendors agreed to take part. And even then, they only joined if they could back out any time they wanted. By the time the test was completed, three of those participants decided to keep the results to themselves. That meant only two vendors -- Ellacoya and ipoque GmbH -- were willing to make their results public, out of an initial list of 28.

Carsten Rossenhovel, managing director of EANTC, says it was unusual for so many vendors to decline such an invitation. However, he believes many ultimately opted out because their products were not up to snuff. "Over time we found out this was because many of the products were still in the early stages of development," he says.

There were two major types of failures that the tested products fell victim to. The first came in accurately identifying and filtering the many different peer-to-peer protocols that people use.

The devices were about 90 percent accurate in identifying sessions for BitTorrent, which is the most popular P2P file sharing protocol. However, the products were less accurate in other sessions, allowing up to 30 percent of traffic in other protocols to pass. In total, 13 different P2P protocols were tested, but only the most widely used were reliably detected.

The second failure was much more important to content owners, as the devices tested were only able to identify traffic by protocol, and not by content -- which isn't helpful for content owners looking to protect their copyrights.

"Service providers want to reduce P2P for network traffic. But media companies are not interested in reducing traffic; they just want to reduce copyrighted content" shared by P2P users, Rossenhovel says.

All of which points to improvement needed from vendors. In the meantime, service providers probably won't stop buying DPI filtering products, even if they're not perfect.

As Rossenhovel says, "If you are a service provider and have a desperate need for a device to control peer-to-peer traffic, you're likely to use a certain solution as long as nothing better is on the market."

The full report, along with detailed results, is available here.

— Ryan Lawler, Reporter, Light Reading