By Monika Ermert, Heise Online
Jul 30, 2008

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Previously, the Internet Engineering Task Force (IETF) has refrained from standardising peer-to-peer (P2P) applications used for filesharing, TV streaming, and other applications. Now the working group is tackling ways to make data traffic between P2P users more effective. At the Dublin developers' meeting there were opponents of an application layer traffic optimisation (ALTO) protocol who could not be won over. However, Jon Peterson, an IETF Area Director for Real-time Applications and Infrastructure, warned that the problem should not be put off. He underscored this by pointing to the interest of P2P companies like BitTorrent.

To the consternation of many internet service providers, like Comcast, 50 to 80 per cent of all data traffic consists of P2P and the share is growing. Comcast's filtering of BitTorrent data traffic is just one example of network operators' attitudes. In an IETF workshop in May, both sides presented their views on how to solve the problem using an "oracle". In addition, Comcast sat down with BitTorrent in March to discuss network management possibilities.

At the centre of the IETF's current efforts is a mechanism that can respond to a P2P user query for the best P2P node. This should solve the problem of the P2P client having to take the long way round to get to a server that has the desired content. According to an IETF expert, a server in Dublin, for instance, may download content from a server in Tokyo even though the same content is available on a server in London.

There are a number of possible solutions: The P4P working group at Yale University has conducted initial testing in the Verizon and Telefonica networks. On the other side of the pond, an EU supported research project is working on a solution called Network-Aware P2P TV Application Over Wise Networks. In spring, Berlin computer science professor Anja Feldmann presented the concept of an "oracle" server, which would deliver a rating list of the closest P2P nodes.

IETF does not want to touch anything that has to do with rating P2P nodes. They believe that the first step should be standardising the interface between P2P applications and the external "information" or "oracle" server that specifies which is the closest, most powerful, or fastest P2P server. In opposition to a push by the Recording Industry of America Association (RIAA) at the IETF workshop, IETF developers want to distance themselves in the planned statement of purpose for the ALTO Working Group from the idea of including any legal issues, such as the question of blocking illegal downloads on the oracle servers.

That IETF developers want to distance themselves from this topic shows just how sensitive it is. The user data from queries leaving the oracle server could also stir other temptations. That is why privacy issues have a prominent place on ALTO's agenda. SIP expert Henry Sinnreich asked in Dublin today "Isn't it enough to ensure that adequate bandwidth is available?", offering an alternative to traffic redirection and monitoring.

Another SIP expert, Henning Schultzrinne of Columbia University, raised the possibility of giving end users more control over data traffic costs. Currently, users face the disheartening possibility of risking a hefty bill for P2P traffic. At his university, it is standard operating procedure to block access to users who have exceeded their 252 gigabyte monthly volume. The Alto architecture, in Schulzrinne's view, could ensure the transparency of options and fees for the user. But the core issue for ALTO is not finding a remedy for peak traffic times, but rather simply the question of efficiency.

(Monika Ermert)

For more on the 72nd IETF Meeting see:

• Website for the IETF meeting in Dublin

News from the 71st IETF Meeting:

• Dispute about new standard for non-English domains
• IETF meeting cuts off all IPv4 connections for a while
• Is DNSSEC the way to go?
• Developers hope for wider use of the DKIM anti-spam protocol
• Measures sought against VoIP spam

(trk)