Traffic and power-aware protection scheme in Elastic Optical Networks

Currently, the need for “greener” telecommunication networks is stimulating research efforts to find new solutions to cope with power consumption and sustainability issues. Exploiting the potential of optical Wavelength Division Multiplexed (WDM) networks for this purpose has been identified as an attractive approach. However, the traditional WDM fixed-grid, where 50 GHz-spaced optical carriers are used with Single Line Rates (SLR), may result in lower efficiency from both the spectral occupation and power consumption perspectives. Higher flexibility can be provided by adopting Mixed Line Rates (MLR) and, especially, the so-called Elastic Optical Network (EON) paradigm, which is enabled by the Orthogonal Frequency Division Multiplexing combined with Coherent Detection (CO-OFDM). In this scenario a finer channel spacing is considered so the spectrum can be best fitted to actual traffic needs. Another critical issue is the network robustness to failures, accomplished by reserving additional resources as a backup for protection. Traditional approaches allocate dedicated (1+1) resources for protection and the peak-rate capacity is reserved in both working and protection paths for every traffic demand. Thus, the power consumed in resilient network is substantially increased compared to the unprotected case. In this paper, we evaluate the impact of the hourly network traffic variation to reduce the power consumed by backup resources, by adapting their rate to the current required bandwidth. We apply this paradigm to the SLR, MLR and EON scenarios and find that, especially in the EON case and for high traffic load conditions, substantial energy savings (up to 27%) can be obtained by exploiting the information on hourly traffic variation.