The disparity between P2P overlays and ISP underlays: issues, existing solutions, and challenges

The proliferation of peer-to-peer applications has generated tremendous traffic in the Internet backbone and has also posed unprecedented pressure on Internet Service Providers. Many P2P applications, oblivious of underlying ISP networks, can lead to inefficient utilization of Internet resources and a significant amount of costly inter-ISP traffic. Recently, increasing efforts have been directed toward mitigating ISP costs from P2P applications while preserving the user perceived service quality. In this article we review state-of-the-art research on P2P applications with particular focus on their topological properties and navigating algorithms with awareness of ISP costs and performances. We discuss ISP-friendly designs in P2P applications by identifying their respective benefits and deficiencies. Based on the lessons we have learned, we further highlight future research challenges and issues regarding the joint design and optimization of P2P system performance and ISP traffic and costs.