Nowadays green IT receives increasing attention because of the requirements of energy-efficiency, on effects that damage the environment and minimize the energy consumption are also a main goal for the economy. The power consumption of information and communication systems is of the same order of the car industry.  All that has of course an influence on the environment: according to several surveys, about 2% of the total CO2 emission is produced by the Information Technology and Communication sector which is as much as the contribution of the whole air traffic and transportation. , 
In this work we analyzed the power consumption of multilayer networks from some different views. In core networks neither simply the optical nor simply the electronical technology can give a cost-effective solution for the problem of the huge power consumption. This idea is supported by some results from the simulation on a model of a multilayer network called the wavelength graph , in which the energy-efficiency is reached by the routing. A simplified cost-function has been constructed in accordance to the routing demands. The results show that through combination of the two technologies the optimal using rate of both type of equipment and the lowest cost route can be achieved. We managed to implement a traffic-based adaptive weighting method which offered the best result in a way of network’s usage of energy-resources. We also made some research on reducing fixed idle power consumption with some new results. In the future I would like to analyze some different methods like selective connectedness , and adapt them to the wavelength-graph.