Graph decompositions with application to wavelength add-drop multiplexing for minimizing SONET ADMs

In a synchronous optical network ring, assignment of source-to-destination circuits to wavelengths must respect traffic requirements and minimize both the number of wavelengths and the amount of terminal conversion equipment. When traffic requirements are approximately equal on all source-destination circuits, the assignment can be modeled as a graph decomposition problem. In this setting, techniques from combinatorial design theory can be applied. These techniques are introduced in a simpler form when every source-destination circuit requires one quarter of a wavelength. More sophisticated design-theoretic methods are then developed to produce the required decompositions for all sufficiently large ring sizes, when each source-destination circuit requires one eighth of a wavelength.