NETp1-04: "Dude, where\´ my Peer?"

Peer to peer (P2P) flows constitute a large portion of Internet traffic meandering through different ISP domains. Hence, it is of prime concern for ISPs to try and gauge the number of active P2P users and where they are located, both inside and outside their respective domains. An analysis of where P2P users are located in the Internet provides an insight into understanding which ISPs harbor a majority of P2P peers, which ones afford most transit to P2P flows, and possibly which ISPs should focus on anti-P2P policies the most. We observe an extremely skewed distribution, approximately 92 to 98% of P2P flows ending in tier 1 and tier 4 ISPs, and just 2 to 8% ending in tier 2 and 3 ISPs. We quantify the role of ISPs in allowing P2P flows to traverse through their domains and observe a similar skewed distribution wherein tier 1 and tier 4 ISPs contribute 92 to 95 % of all hops on most P2P flows. Moreover, we compare P2P traffic with http and Internet radio traces to uncover potential parameters to differentiate between these types of flows. We present detailed results based on active measurements taken over a 30 day period, spanning over half a million P2P flows, collected from measurements employing a number of popular P2P clients hosted inside two popular ISPs.