Brown-field gradual migration planning toward spectrally-spatially flexible optical networks

In this paper, we motivate a brown-field migrationplanning as a cost-efficient procedure to scale the capacity ofshort-term realizable elastic optical networks (EONs), graduallyconverting them into spectrally-spatially flexible optical networks(SS-FONs). After a formal statement of the brown-field EON toSS-FON migration planning problem, a Stochastic Iterated LocalSearch (SILS) metaheuristic is presented to solve it in realistictime-scales. Using the proposed metaheuristic, we study themigration of two different reference backbone EONs to SS-FONsbased in realistic traffic forecasts up to year 2031, accountingfor both unicast and anycast traffic types. The obtained resultsalso serve to highlight the good performance of the proposedSILS metaheuristic versus alternative heuristic approaches usedas benchmark.