Multi-stage Optical Packet Switches with Shared Wavelength Converters: Practical Solutions and Performance

Multi-stage optical packet switching fabric based on the broadcast-and-select principle is considered to implement the shared-per-node wavelength conversion scheme. This approach fairly allows to combine contention resolution in the wavelength and space domains. Scheduling algorithms are proposed to control optical packet forwarding in synchronous context. A simple analytical framework to calculate the packet loss probability in different traffic contexts is provided and validated by simulation. A possible scheme to add contention resolution in the time domain is also discussed. The results aim at showing how the sharing of wavelength converters impacts on node performance, the grade of sharing achieved with respect to the reference shared-per-node architecture, and at providing a meaningful support for cost-performance benchmarking studies.