A MILP-Based Heuristic for Energy-Aware Traffic Engineering with Shortest Path Routing

Internet energy consumption is rapidly becoming an issue due to the exponential traffic growth and the rapid expansion of communication infrastructures worldwide. We address the problem of energy-aware intra-domain traffic engineering in networks operated with a shortest path routing protocol. We consider the problem of switching off (putting in sleeping mode) network elements (links and routers) and of adjusting the link weights so as to minimize the energy consumption as well as maximizing a measure of effectiveness of the routing weight configuration. We propose a three-phase MILP-based heuristic for tackling this multi-objective problem with priority (first minimize the energy consumption and then the overall cost of link utilization), which exploits the IGP-WO heuristic proposed for optimizing the link weights so as to minimize the total cost of link utilization. For comparison purposes, we also developed a greedy randomized search procedure with path-relinking. The computational results for four real network topologies and different types of traffic matrices show that it is possible to switch off a substantial number of core nodes during low and moderate traffic periods, while guaranteeing the same point-to-point service quality and moderately increasing the network total cost of link utilization.