Implications of the Wavelnength Conversion Cascading Constraint on Two Optical Routing Algorithms

In wavelength division multiplexed (WDM) optical networks, each wavelength conversion performed along the light path of the connection causes some signal-to-noise deterioration. There is therefore an upper bound (threshold) on the number of wavelength conversions that a signal can go through when it is switched optically from its source to its destination. Our test results have shown that the blocking performance of optical routing could deteriorate significantly under the impact of the conversion cascading constraint. In this paper, we review the negative impact of wavelength conversion cascading on the performance of all-optical routing and we examine the implications of the presence of the conversion cascading constraint on the validity of the performance results for two previously proposed routing protocols for optical networks.