부산대학교 도서관

In this paper, the new problem of routing and spectrum resources assignment in multi-band optical orthogonal-frequency-division-multiplexing (MB-OFDM) metropolitan (metro) networks is analysed. Differently from the routing and spectrum assignment problem in elastic optical networks, in order to serve a connection request, routing, wavelength and band assignment (RWBA) is needed in MB-OFDM networks. The key point in the RWBA problem is that a band assignment algorithm needs to be considered that, when associated with the wavelength assignment algorithm, may lead to considerable differences in network blocking performance. In this direction, besides traditional heuristics, such as First-Fit and Random, a new heuristic to perform band assignment, called Extremes, is proposed and analysed. Numerical simulations show that different configurations in number of wavelengths and number of bands per wavelength may present considerable difference in blocking probability. Moreover, a correct choice of heuristics in the RWBA may also result in large difference in blocking performance, and having the Extremes heuristic with the best blocking performance.