Energy Savings with Multilayer Traffic Engineering in Future Core Networks

The main advantage of multilayer automatically switched IP-over-MPLSover-optical networks is their ability and their flexibility to adapt to the variations of the offered traffic. Multilayer traffic engineering mechanisms exploit this characteristic and perform traditional rerouting enriched with online IP logical topology reconfiguration. These mechanisms aim at optimizing resource usage and maximizing QoS, e.g. in terms of bandwidth, throughput and delay. Recently except from performance, energy efficiency in backbone core networks has gained much attention. In this article, we will examine how multilayer traffic engineering techniques can help to increase energy savings and minimize energy consumption. As we will present the simultaneous optimization of routing and minimization of the number of active network elements leads to significant energy savings. We will propose an adaptive algorithm for IP/MPLS/WDM with traffic grooming networks, which will aggregate traffic flows in the same LSPs and consequently in the same optical wavelengths. Additionally, this algorithm has the objective to reduce energy by switching off unused router line cards. In this way routing is optimized and the topology of IP layer is adapted to the variations of traffic in network. To achieve this, LSPs (links and optical channels) must be recomputed Journal of Green Engineering, Vol. 2, 195–214. c © 2012 River Publishers. All rights reserved. 196 V. Foteinos et al. every time a new traffic flow enters network, using a specific cost function to compute link and channels weights according to their current availability.