Wavelength routing and optical burst switching in the design of future optical network architectures

Wavelength-routed optical network (WRON) architectures potentially simplify routing and processing functions in high-capacity, high-bit rate WDM optical networks. With the inherent low latency these are relatively easy to design with a number of efficient routing and wavelength assignment protocols proposed to date. However, the pressure to optimise network resources and protocols for IP traffic has focused attention on network architectures which can rapidly adapt to the changes in traffic patterns as well as traffic loads. Candidate architectures for future core networks include optical burst switching (OBS) with or without end-to-end capacity reservation acknowledgement and with dynamic wavelength routing functions. Typically packets are aggregated (and queued) at the edge routers of the network (by routing destination or class of service) and routed over a bufferless core. Appropriately timed aggregation of packets into "bursts" is, therefore, a way to reduce the processing overhead and buffering, providing packet loss and delay requirements for a given class-of-service can be satisfied, although the design trade-offs between the reduction in processing and the control requirements for resource allocation require further study.