On Randomness in ISP-friendly P2P Applications

P2P networking is a popular technology for sharing large files efficiently without using powerful servers. The goal for a P2P file sharing application is to minimize the download time experienced by the peers. However, the efficiency of a P2P network comes at the expense of excessive network utilization. ISPs want to control the network utilization of P2P applications, and in particular it is desirable to minimize the inter-ISP traffic. The often contradicting interests of applications and network owners have led to the search for an ISP-friendly P2P application that reduces inter-ISP traffic while maintaining the high file-sharing efficiency. Existing solutions propose to localize most of the P2P traffic within the ISP, while randomly selecting a few external peers to ensure the global spread of content. However, these proposals disregard the inherent randomness that will naturally exist in P2P systems. In this paper, we analyze the different sources of inherent randomness in ISP-friendly P2P systems, and show that they can have a significant impact on performance, and therefore must be taken into account when designing new solutions.