Adaptive Routing and Spectrum Allocation in Elastic Waveband Switching Optical Networks

Several lightpaths can be switched as a single entity, so that only one pair of transmission ports will be consumed at every intermediate node, which facilitates port savings in Wavelength-Division Multiplexing (WDM) optical networks. However, in Elastic Optical Networks (EONs), the lightpath does not occupy a fixed wavelength but a group of continuous and orthogonal subcarriers with the flexible bandwidth provisioning adjusted under the distance adaptive modulation. This means that the waveband switching in EONs involves the multi-dimensional allocation of the subcarrier, wavelength and even waveband, with the high dynamic. In this paper, to minimize the port cost and efficiently utilize spectral resources with the help of the complementary advantages of waveband switching and EONs, we propose the modulation-adaptive algorithm followed by a new waveband switching strategy. Simulation results demonstrate that our approach is cost-effective and improves the spectral efficiency of elastic waveband switching optical networks.