Hierarchical networks: for optical communications

Proposes two-level hierarchical networks for optical communications. At the first level, each cluster of users can be connected either via a ShuffleNet (SH) or a de Bruijn network (dB). At the second level, all the clusters in the system can be connected by two rings in opposite directions (SH/Ring and dB/Ring), or a de Bruijn network (dB/dB), or a ShuffleNet (SH/SH). The performances of the ShuffleNet, the de Bruijn networks, and the hierarchical networks: SH/Ring, dB/Ring, dB/dB and SH/SH, are compared. For communications with a high locality, the hierarchical networks are shown to be very effective