Channel sharing in multi-hop WDM lightwave networks. (Do we really need more channels?)

A local lightwave network can be constructed by employing two-way fibers to connect nodes in a passive-star physical topology, and the available optical bandwidth may be effectively accessed by the nodal transmitters and receivers at electronic rates using wavelength division multiplexing (WDM). The number of channels in a WDM network is technology-limited and is usually less than the number of nodes in the network. We provide a general method using channel-sharing to construct practical multi-hop networks under this limitation. The method is applied to a generalized shuffle-exchange-based architecture. We also develop a general modeling procedure for the analysis of shared-channel multi-hop WDM networks. The analysis enables the study of the effects of two important parameters governing the performance of such networks, namely propagation delay and number of channels. Our analysis leads us to a counter-intuitive result: it is sometimes better to have fewer channels than a larger number of channels. We obtain an estimate for the optimal number of channels as a function of the number of nodes, propagation delay, and traffic intensity