A RWA performance comparison for hybrid optical networks combining circuit and multi-wavelength packet switching

This paper compares several routing and wavelength assignment algorithms for a hybrid optical network architecture combining optical circuit switching (OCS) and multi-wavelength optical packet switching (MW-OPS). In this network, due to the fact that wavelength resources in a fiber are shared between OCS and MW-OPS and in MW-OPS each multi-wavelength optical packet must be encoded into continuous, free wavelengths along the route, the choice of routing and wavelength assignment (RWA) algorithms critically influences the performance of wavelength utilization in the network. We compare several RWA algorithms in the network by simulation. As a result, the MML-FF RWA algorithm which combines the first-fit (FF) wavelength assignment algorithm and the maximum matched lambda (MML) routing algorithm outperforms the others in both wavelength utilization and load-balancing. Furthermore, the number of TWCs to achieve the optimum performance in the network is at most 30 % of the product of the number of ports in a core node and that of wavelengths in a fiber.