From energy-efficient networking to ZEN

Energy-efficiency has become a hot topic in networking research. Several large international research projects have been activated in recent years on this subject. Examples are GreenTouch [1], conceived at Alcatel Lucent Bell Labs, TREND, EARTH, ECONET, C2POWER, CHRON, STRONGEST, Fit4Green, COST IC 804 [2,3,4,5,6,7,8,9], all funded by the European Commission through its 7th Framework Programme, and many national research projects, such as COOL SILICON in Germany and EFFICIENT in Italy. In addition, most equipment manufacturers feature their own internal research projects on this topic, such as GREAT in Huawei. The objective of all these research efforts consists in the reduction of the energy consumption of data networks, but their targets vary, from the 20% saving in today's networks quite realistically claimed by TREND, to the reduction by a factor 1000 in future networks somewhat optimistically foreseen by GreenTouch.