Energy Efficiency of Voice-Over-IP Systems
The authors identified the key components that are implemented on servers in a c/s VoIP system and by super nodes in a p2p VoIP system (Skype). They presented a model for understanding power consumption of c/s and p2p VoIP systems. They performed a number of experiments to determine the power consumption of different components of c/s and p2p VoIP systems. The model, analysis, and measurements indicate that for VoIP systems used as a replacement for always-on PSTN system, the power consumed by hardphones and connected network devices (broadband modems, home routers, and enterprise switches) overwhelmingly dominate the total power consumed by the VoIP system and the per user per month cost is less than a dollar in such systems.