Superfilter technique in SDN-controlled elastic optical networks [Invited]

In flexigrid elastic optical networks, filtering cascade effects strongly affect the overall transmission performance. To avoid these detrimental impairments, each lightpath is typically configured, in an independent way, to encompass additional spectrum resources. Thus, the flat central region of the traversed filters are exploited and their transition region around the cutoff frequencies is avoided. However, handling lightpaths independently leads to less efficient spectrum utilization. In this study, we propose a novel technique, called superfilters, which enables different lightpaths, with different source-destination pairs, to coexist within the same flat region of a single filter configuration. That is, the technique consists of a pathcomputation strategy that applies differentiated configurations of lightpath traversed filters, which are decoupled from head-end lightpath configurations. Simulative transmission results are provided to assess the benefits of the proposed technique. Then, an experimental implementation is presented, including a software-defined networking implementation successfully applied to a flexigrid network testbed.