Protection in optical transport networks with fixed and flexible grid: Cost and energy efficiency evaluation

The ever-increasing Internet traffic demand introduces new challenges for telecommunications carriers. Telecom networks will have to be upgraded to cope with the new capacity requirements. However, deploying enough capacity is not the only requirement for network operators. The impact of new technologies in terms of capital investment and energy consumption becomes a key issue. There is a special interest in investigating new mechanisms and technologies to improve the energy efficiency of future networks, while maintaining the high reliability and service availability of current optical transport networks. This article evaluates the energy- and cost-efficiency of an innovative flexible-grid orthogonal-frequency-division-multiplexing (OFDM) -based network and compares them with those for conventional wavelength-division-multiplexing (WDM) networks. Due to the importance of resilience in optical transport networks, the study considers and evaluates different protection schemes. The results demonstrate the potential energy efficiency improvements that can be achieved by an elastic OFDM-based technology, especially when a shared protection scheme is adopted, and give an insight into the potential cost benefits that such a novel technology can offer to telecommunication carriers.