Abstract: System and method for dynamically assigning wavelengths wavelength division multiplex (“WDM”) ring networks is described. In one embodiment, the invention comprises a method for dynamic wavelength assignment on a ring in a WDM network comprising, for each new requested traffic flow from a source node to a destination node on the ring, for each segment on a path around the ring between the source and destination nodes, classifying the new requested traffic flow into one of a set of spatial relationship types for each existing wavelength; determining a corresponding number of optical-to-electrical and electrical-to-optical (“OEO”) interfaces needed for each spatial relationship type selected for each segment; determining the total number of OEO interfaces needed for the entire path between the source and destination nodes along the ring; and selecting the existing wavelengths that minimize the OEO interfaces.

Abstract: A technique for assigning a wavelength to a new flow in WDM ring networks that minimizes the total number of OE and EO interfaces added to the network is described. A SuperSet comprising thirteen cases representing the spatial relationship between existing wavelengths and the new flow is identified. An OE/EO table identifies for each case in the SuperSet the total number of OE and EO interfaces added. A QoS table identifies an order of priority for selection of a wavelength given a traffic class of the new flow. A mapping of traffic in the network to one of the SuperSet cases is identified and the optimal case that minimizes the total number of OE/EO interfaces added is selected using the OE/EO table. In one embodiment, a wavelength corresponding to the selected case is assigned to the flow. In another embodiment, a determination is made using the QoS table and wavelength grades whether assigning the selected wavelength will result in an acceptable performance for all network traffic.