The continuous growth of traffic and the energy consumption of network equipments can limit the deployment of large-scale distributed infrastructure. This work aims to improve the energy efficiency of backbone networks by dynamically adjusting the number of active links according to network load. We propose an intra-domain software-defined network approach to select and turn off a subset of links. The SPRING protocol (a.k.a. segment routing) is used to make our algorithms converge faster. The algorithms—implemented and evaluated using the OMNET++ discrete event simulator—can achieve energy savings of around 44 % when considering real backbone networks.