In this paper, the power consumption of a transparent circuit-switched wavelength-division multiplexing (WDM) optical network is evaluated, considering client flow protection requirements and the daily traffic variability. Moreover, a simple heuristic algorithm is applied to the considered network scenario to reduce the power consumption of optical links. When traffic load decreases, the algorithm tries to switch off optical links according to several heuristic criteria that take into account the power consumption parameter of links, some topological consideration and the congestion of each fiber. By performing such an optimization, applying the best link-ordering criterion, it is possible to save an amount of power from 28% up to 86% of the power consumed by optical links on the basis of the traffic load. This leads to an average energy saving of 35% with respect to the energy consumed by the whole optical network. Moreover, we evaluate the impact of network design parameters on the proposed algorithm and the network power consumption. Results show that, for a 18-node network supporting an average traffic of 75 Gbits/s between each node pair, a number of wavelengths equal to 80 can drastically reduce the power consumption of optical links

This paper proposes a novel power-aware routing and wavelength assignment (PA-RWA) algorithm to be applied to a transparent wavelength division multiplexing (WDM) optical network. The proposed algorithm aims at improving the energy efficiency of the optical network by leaving unused optical fibres as much as possible in order to minimize the number of optical amplifiers kept active in the network. A dynamic lightpath establishment scenario is considered and results are compared with other routing algorithms showing that the proposed algorithm can drastically reduce the power consumption for any value of traffic load

Energy saving in telecommunications networks has become a well established topic in the research community. We look at the electrical and optical layers of IP-over-WDM networks, and present a list of evaluation criteria for the Energy-Aware Adaptive Routing Solutions (EA-ARSs) from the perspective of a network operator. Furthermore, we briefly explain the EA-ARSs originating from European Union's TREND, the FP7 Network of Excellence, show saving of energy consumed by Line Cards (LCs) on a reference scenario, and use the evaluation criteria to identify the next steps toward introduction of the EA-ARSs into real operation.

This paper focuses on the energy consumption minimization problem of an optical transport network extending over a very wide area. In particular, the specific problem of power-aware routing and wavelength assignment (PA-RWA) is addressed considering a transparent multi-fiber optical network. An integer linear programming formulation is provided for the static lightpath establishment problem and a few heuristics are proposed to solve the problem in the case of dynamic lightpath establishment. To solve the routing problem we propose a novel algorithm named load based cost; it is based on a cost function that considers the load of each optical fiber to compute link weights. We also propose two new wavelength assignment algorithms: the first one is derived from the first fit heuristic whilst the second one is based on an innovative approach. It works like a least cost routing algorithm assigning a cost to each wavelength for each link in the path and then minimizes the total cost. Our proposal is compared with a number of already known RWA algorithms showing that it is able to reduce the power consumption of the network by about 20-30%, depending on the amount of traffic treated, with respect to state of the art algorithms with a difference of about 10% with respect to the lower bound. In order to provide a complete analysis of the feasibility of the proposed heuristics, the blocking probability is evaluated: the results show that, unlike the other power-aware algorithms here considered, our proposal shows a low impairment with respect to the least congested path-first fit alternative. Another important result regards the better performance of the proposed wavelength assignment algorithm with respect to first fit

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