Date Added: Mar 2012
Multiple node architectures are possible for WDM networks. These architectures strongly condition the cost of optical network planning and traffic engineering. This paper aims first to introduce the four optical switching systems currently considered; namely Optical CROSS Connect (OXC), Optical Circuit Switching (OCS), Optical Packet Switching (OPS), and Optical Burst Switching (OBS). Then a detailed description of a multi-layer EXC/OXC node architecture is presented. Such architecture can handle full-wavelength circuits as well as sub-wavelength electrical connections. The major functionalities of this EXC/OXC node (add, drop, switching, and grooming) are modeled by means of an auxiliary graph.