Energy optimization in IP-over-WDM networks

The energy crisis and environmental protection are gaining increasing concern in recent years. ICT (Information and Communication Technology) has a significant impact on the total electricity consumption all over the world. Telecom networks, being an important part of ICT, consume significant energy since more network equipment is deployed annually. Specifically, in IP-over-WDM networks, energy is consumed by network elements at both IP and WDM layers. Routers in the IP layer are the largest energy consumer in this architecture, and current network infrastructures have no energy-saving scheme, so a large amount of energy is wasted when traffic load is low. In this paper, we propose a novel approach to save energy in IP-over-WDM networks by shutting down idle line cards and chassis of routers based on time-of-the-day network traffic variation. A method based on Mixed Integer Linear Programming (MILP) is proposed to ensure that the energy cost incurred by the IP routers and optical cross-connects is minimized by our approach. We also propose some possible approaches to minimize potential traffic disruption when the network elements are shut down.