Abstract
In this paper, we present a comparison of the blocking performance in unidirectional and bi‐directional wavelength routed ring networks. This performance comparison reveals that, for the same load per node and equal number of wavelengths per link, the performance of a unidirectional ring with N nodes is very close to the performance of a bi‐directional ring with 4N nodes. This comparison also suggests that, for the same number of nodes and equal number of wavelengths per link, the performance of a unidirectional ring network with a load per node of ρ is similar to the performance of a bi‐directional ring network with a load per node of 4ρ. An explanation is presented for this four‐fold capacity increase of bi‐directional rings over unidirectional rings, regarding number of nodes or loads per node.