A Generalized Framework for Analyzing Time-Space Switched Optical Networks

Recent advances in photonic switching have paved the way for realizing all-optical time switched networks. The current technology of Wavelength Division Multiplexing (WDM) offers bandwidth granularity that match peak electronic transmission speed by dividing the fiber bandwidth into multiple wavelengths. However, the bandwidth of a single wavelength is too large for certain traffic. Time Division Multiplexing (TDM) allows multiple traffic streams to share the bandwidth of a wavelength efficiently. While introducing wavelength converters and time slot interchangers improve network blocking performance, it is often of interest to know the incremental benefits offered by every additional stage of switching. As all-optical networks in future are expected to employ heterogeneous switching architectures, it is necessary to have generalized network model that allows to study these networks under a unified framework. In this paper, a network model, called Trunk Switched Network (TSN), is proposed to facilitate modeling and analysis of such networks. An analytical model for evaluating the blocking performance of a class of TSN’s has also been developed. Using the analytical model, it is shown that a significant performance improvement is obtained with a time-space switch with no wavelength conversion at each node in a multi-wavelength TDM switched network. Keywords—Opticalnetworks, WDM/TDM switching, Performance modeling