Network resource advantages of bidirectional wavelength-path switched ring

Wavelength-division-multiplexing (WDM) transport ring-network architectures analogous to conventional time-division multiplexing systems are disadvantageous in that they require either an increase in the necessary number of wavelengths, or long optical-transmission brought about by loop-back, thus raising costs. We have studied a transport WDM ring network in which the switching unit is wavelength and the standby resources are shared. Its advantages are confirmed by evaluation of the necessary number of wavelengths, the maximum circumference for a transparent ring, and the number of 3R-regenerators (3R: reshaping, regeneration, and retiming) for a large-sized opaque ring network.