Abstract—The power consumption in Information and Communication Technologies (ICT) networks is growing year by year; this growth presents challenges from a technical, economic and environmental point of view. This has lead to a great number of research publications on ‘green’ telecommunication networks. In response, a number of survey works have appeared as well. However, with respect to backbone networks most survey works (a) do not allow for an easy cross-validation of the savings reported in the various works, (b) nor do they provide a clear overview of the individual and combined power saving potential. Therefore, in this work we survey the reported saving potential in IP-over-WDM backbone telecommunication networks across the existing body of research in that area. We do this by mapping more than 10 different approaches to a concise analytical model, which allows us to estimate the combined power reduction potential. Our estimates indicate that the power reduction potential ...