In order to satisfy the need for the critical computing resources, many data center architectures proposed to house a huge number of network devices. These devices are used to achieve the highest performance in case of full utilization of the network. However, the peak capacity of the network is rarely reached. Consequently, many devices are set into idle state and cause a huge energy waste leading to a non-proportionality between the network load and the energy consumed. In this paper, we propose a power-aware routing algorithm that saves energy consumption with a negligible trade-off on the performance of the network. The idea is to keep active only the source and destination devices and the vital nodes participating in the communication. Vital nodes in the network are calculated only once and can be used with a constant time complexity. Besides its short computation time, our routing algorithm guarantees also a high performance and shows over 50% of energy saving.