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Peer-to-peer (P2P) traffic is the bane of both ISPs trying to keep control of their bandwidth resources and content companies worried about file sharinwg software that enable video and music 'piracy'.
P2P filtering products that use deep packet inspection (DPI) have been touted as the optimal solution, but as P2P becomes an increasingly legit option for moving multimedia across the network, carriers are starting to shift their strategy from blocking P2P to making it run more efficiently.
P2P traffic filtering is a tough nut to crack in part because P2P apps are usually designed to work around potential network blocks, says Matt Kolon, VP of technical operations for Asia-Pacific at Juniper Networks.
'They move around all the time and drift from port to port and do things to disguise the protocol and obfuscate that it's P2P,' he told First Mile.
Carriers hunting for suspected P2P traffic tend to rely on blunt policies based on 'volumes and circumstantial evidence' rather than actually knowing what the traffic is, he adds.
DPI filtering is touted as a smarter and more efficient way of spotting P2P and throttling perps. However, a recent independent test concluded that many DPI filters may not be up to the job.
The European Advanced Networking Test Center (EANTC) was commissioned by Internet Evolution and French music industry association SNEP (Syndicat National de l'ïâ‚¬–ition Phonographique) to test carrier-grade DPI products under network conditions. Perhaps tellingly, 23 of the 28 vendors invited to participate refused, and of the five who accepted, only two - Ellacoya and ipoque - were willing to make the results public.
The test results from Ellacoya and ipoque were mixed. Both were able to detect BitTorrent and eDonkey traffic (the two biggest P2P protocols on the web) with accuracy rates over 90%, but couldn't distinguish traffic by content.
The latter result is arguably the more significant, because ISPs are now faced with the growing legitimacy of P2P as a content distribution tool. Services like Joost, Babelgum and Limewire, for example, use P2P to legally distribute multimedia content. VeriSign's Kontiki P2P platform is used by broadcasters and enterprises like Charles Schwab and Ernst & Young.
Consequently, some carriers are learning to live with P2P. In the US Comcast is working with P2P players like BitTorrent while other P2P companies like Pando Networks, PeerApp and Velocix say they are also in active discussions with ISPs.
Meanwhile, Pando is approaching the bandwidth issue from another angle: making P2P more bandwidth-efficient via P4P (Proactive network Provider Participation for P2P). The Distributed Computing Industry Association (DCIA) P4P Working Group, which Pando co-founded, is working with ISPs and P2P providers to develop a protocol that lets service providers communicate information about network conditions to P2P clients that would, in essence, allow them to select peers more efficiently rather than at random. That, ostensibly, means less burden on backbones and lower network opex.
Pando and Verizon recently released the results of the first major P4P field test at a DCIA P2P conference last month. Results: increased delivery speeds by up to 898% across international broadband networks, while cutting international data transfers between ISPs by over 75%.