Renewable energy in IP over WDM networks

Recent studies have shown that the Information and Communication Technology (ICT) industry is responsible for about 2% of the global emission of CO₂ and this percentage is expected to increase as the Internet expands in bandwidth and reach. In this paper, we propose the use of renewable energy in IP over WDM networks to minimize CO₂ emissions. A Linear Programming (LP) model is proposed to optimize the use of renewable energy. A novel heuristic is developed for improving renewable energy utilization based on Multi-hop-bypass. Compared with the Non-bypass heuristic, simulation results indicate that the CO₂ emissions of the hybrid power IP over WDM network are reduced significantly, by 45% ~ 55%, and the new heuristic has little impact on the QoS. In order to identify the impact of the number and the location of nodes that employ renewable energy on the non-renewable energy consumption of the network, we also develop another LP model. Simulation results show that using renewable energy at nodes at the centre of the network maximizes the benefit.