Towards a dynamic hierarchical cross-connecting without wavelength conversion in multi-fiber WDM networks

We consider the problem of optical node design to optimize the use of hierarchical cross-connects (HXC) in order to reduce the optical cross-connect (OXC) complexity while maintaining a low blocking probability when working with dynamic traffic demands. The HXCs implement an optical bypass, at coarse granularity using the wavelength banding technique with waveband cross-connects (WBXC), and, at fine granularity, using wavelength cross-connects (WXC). Reducing the possibility of fine granularity switching results in reducing the OXC complexity at the expense of increasing the blocking probability. In particular, we do not allow the use of wavelength converters in order to reduce the global cost further. Two parameters, μ and β, define the optical node architecture with a calculated complexity reduction ratio and a simulated blocking probability. Fixing a maximum blocking probability and a minimum complexity reduction results in choosing μ and β, and hence the node design, for a maximum given traffic load.