Multi-period traffic engineering of resilient networks for energy efficiency

In this paper we consider the problem of minimizing the energy consumption of IP networks, exploiting the traffic variations over a set of time intervals, while guaranteeing the network QoS and survivability. Energy savings are achieved by putting into sleep mode cards and chassis, when they are not necessary. Network survivability is based on a dedicated protection scheme, wherein a dedicated backup path is assigned to each demand. The multi-period optimization is constrained by inter-period limitations necessary for guaranteeing network stability. Both exact and heuristic methods are proposed. Results obtained with realistic networks operated with flow-based routing protocols (i.e. MPLS) show that up to 60% of the energy savings can be achieved without negatively affecting network resiliency.