Should ISPs adopt hybrid CDN-P2P in IP-over-WDM networks: An energy-efficiency perspective?

Content based services are becoming more popular in recent times. Traditional content distribution networks (CDN) are being employed for efficient content hosting and distribution. To increase scalability and reduce the cost of content distribution, peer-to-peer (P2P) systems are being considered to complement the traditional CDN systems in a hybrid manner. Research works and real life deployments have shown that hybrid CDN-P2P systems are feasible, cheap, and scalable options. However, with increasing concern for energy consumption and hence carbon footprint, energy efficiency of such a hybrid system must be taken into consideration before wider implementation. In our study, we analyze the energy consumption of hybrid CDN-P2P systems and provide indicators to help make decision for service providers. We show that the hybrid systems not only help the CDN providers to reduce server bandwidth, but also reduce a significant amount of energy in the core network. For a moderately popular content, core network will consume 20-40% less energy with a hybrid system compared to a traditional CDN. This will provide incentive for the service providers to adopt hybrid systems and reduce carbon footprint and operational expenses.