Niewiadomska-Szynkiewicz, E; Sikora, A; Arabas, P; Kamola, M; Malinowski, K; Jaskóła, P; Marks, M
An important part of the modern computer networks design is to develop novel technologies, architectures and control mechanisms for network devices enabling power saving by adapting network capacities to current traffic loads and user demands. We describe centralize and hierarchical control frameworks for reducing power consumption in backbone computer networks. The implementation of these frameworks provides the local control mechanisms that are implemented in the network devices level and network-wide control strategies implemented in the central control level. In this paper, we focus on network-wide algorithms for calculating the power status of network devices and the energy-aware MPLS routing for recommended network configuration. We enumerate several possible formulations of a network energy saving optimization problem with continuous and discrete variables. We discuss the limitations of these approaches and problems with their application to power control in real networks. We propose the relaxation of the complete binary problem formulation assuming full routing and energy state of all devices calculation, and the algorithm to solve it. Our formulation is based on a heuristic approach that leads to a continuous optimization. The evaluation of the optimization scheme through simulation is presented in the final part of the paper.