Wavelength-routed or burst-switched optical network?

Abstract

Although the quasi-static wavelength-routed optical networks (WRONs) are relatively simple to analyze and design, it has been suggested that these may not be sufficiently flexible or adaptive to be able to respond to dynamically-varying traffic loads and service diversity. An alternative approach, termed wavelength-routed optical burst-switching (WROBS), assumes an obligatory end-to-end acknowledgement, and could guarantee a deterministic delay and proposes the use of dynamically-assigned wavelengths for routing lightpaths. Here packets at the network edge are electronically aggregated into bursts according to their destination and class of service (CoS) in separate buffers on the time-scale of milliseconds, which is a typical forwarding time of IP routers. At these time-scales the reservation of resources along the path before sending the burst is feasible, allowing service guarantees. The two OBS approaches are described in comparison with the conceptually much simpler quasi-static WRONs, together with current analysis and design questions.