Hierarchical networks for optical communications

ShuffleNet and de Bruijn networks have been proposed as multihop lightwave networks based on wavelength division multiplexing (WDM). With multihop lig htwave networks, few fixed wavelength transmitters;receivers are assigned t o each user, eliminating the need for wavelength agility and pretransmissio n coordination. These networks have been shown to be very effective for uni form traffic. For communications with high locality, we propose two-level h ierarchical networks. At the first level, each cluster of users can be conn ected either via a ShuffleNet (SH) or a de Bruijn network (dB). At the seco nd level, all the clusters in the system can be connected by two rings in o pposite directions (SH/Ring and dB/Ring), a de Bruijn network (dB/dB), or a ShuffleNet (SH/SH). The performance of ShuffleNet, de Bruijn networks, and the hierarchical networks SH;Ring, dB/Ring, dB/dB, and SH/SH is analyzed. For communications with a high locality, the hierarchical networks are show n to be very effective. (C) 2000 Academic Press.