A Routing and Spectrum Assignment Heuristic for Elastic Optical Networks under Incremental Traffic

In Spectrum-sliced Elastic Optical (SLICE) networks, based on Orthogonal Frequency Division Multiplexing (OFDM), several signals can be sent into the same fiber optical link, each signal modulated by tightly packed orthogonal sub-carriers that can be adjacently allocated to satisfy different bandwidth requirements. The bandwidth allocation in such fine-granularity OFDM-based optical network is more efficient than in networks based on Wavelength Division Multiplexing (WDM), but with an increased complexity. Such problem is known as the Routing and Spectrum Assignment (RSA). In this paper, we propose a RSA heuristic algorithm to minimize the maximum load and balance the traffic load on the network, while minimizing the number of hops in the established lightpaths. The proposed algorithm is compared to the shortest path allocation algorithm for incremental traffic simulations. The results show that the proposed heuristic algorithm can minimize the maximum load on the network, balance the traffic between the links, and save resources for future requests. Furthermore, the analysis of the blocking characteristics shows that the proposed heuristic can postpone traffic blocking, although the effectiveness can vary depending on the network topology and also on the maximum amount of available sub-carriers.