A comparative blocking analysis for time-driven-switched optical networks

Time Driven Switching (TDS) is a recently-proposed switching technique that allows to switch “fractions” of wavelengths (called Synchronous virtual Pipes, SVPs) directly in the optical domain, exploiting the time-coordination of all network components. In this paper a new performance-evaluation model for TDS is proposed and discussed. Using the new model, we conduct a performance comparison between TDS and Optical Circuit Switching (OCS), a well-established optical switching technology. Our analytical results demonstrate the advantages of TDS in terms of blocking probability, thanks to its flexibility in choosing a higher number of paths to establish connection requests. Specifically, even though in TDS networks we have to account for the contribution to the blocking probability due to time blocking, this technique provides a finer (sub-lambda) granularity of wavelength channels if compared to OCS, thus allowing the possibility of routing the requests through a higher number of paths, and according to the SVP granularity rather than the entire wavelength capacity as for OCS.