The objective of this project is to propose a methodology for resource consolidation, which minimizes the power consumption of a large network, in which the resource overprovisioning is quite big. The project focuses on the operation of core MPLS networks. The proposed approach is based on a Software Defined Networking (SDN) scheme with a reconfigurable centralized controller, which turns off network elements (nodes/links). The switch on/off pattern of the elements is determined by a dynamic database, based on customers’ consumption statistics and real time network statistics. The proposed methodology describes the process of identifying time periods with lower traffic demand; ranking the network elements, based on their utilization and criticality; rerouting the traffic off the least utilized elements; and finally switching off the appropriate nodes or links. An algorithm for traffic rerouting, based on MPLS traffic engineering techniques is proposed and its performance is evaluated in terms of the achieved energy efficiency in accordance with predefined connectivity and quality of service constraints.