Optical WDM network having mixed wavelength routing and fiber routing

摘要

An optical wavelength-division-multiplexing (WDM) network has at least one transit node, where a majority of received channels are destined for a remote node, and at least one hub node, where a majority of received channels are switched to a local destination. The network follows a channel-level protection scheme, and at least one of the nodes has a cross-connect switch of a tandem design with a wavelength switch portion optically positioned in a feedback path of a space switch portion. Alternatively, the transit node has a tandem switch design, where the space switch interfaces with the network fibers, and the hub node has at least a wavelength switch that interfaces with the network fibers. The capacities of the respective wavelength and space switch portions of the tandem cross-connect are configured according to the expected ratio of local traffic to passthrough traffic.