A recursive algorithm to reduce the number of wavelength converters in support of multiple light-trees

Summary form only given. Media content delivery and more in general Cloud related data traffic can highly benefit from the availability of multicast connections in the optical transport network. One specific case is represented by optical multicast trees (light-trees), which are established in the wavelength division multiplexing (WDM) layer. With a light-tree, the optical signal from the root of the multicast session is propagated and split optically till the multicast leaves are all reached. To avoid blocking due to already reserved (unavailable) wavelengths, the creation of a light-tree may require a change of the signal wavelength which is assigned to some of the tree links, in which case wavelength converters (WCs) are required for the light-tree to be created. WCs are pricy and consume energy, thus a wisely designed network must minimize the required number of WCs.