CHANNEL SHARING IN MULTIHOP WDM LIGHTWAVE NETWORKS - DO WE NEED MORE CHANNELS

A local lightwave network can be constructed by employing two-way fibe rs to connect nodes in a passive-star physical topology, and the avail able optical bandwidth may be accessed by the nodal transmitters and r eceivers at electronic rates using wavelength-division multiplexing (W DM). The number of WDM channels, w, in such a network is technology-li mited and is less than the number of network nodes, N, especially if t he network should support a scalable number of nodes. We describe a ge neral and practical channel sharing method, which requires each node t o be equipped with only one transmitter-receiver pair, and in which ea ch WDM channel is shared in a time-division multiplexed fashion. We al so develop a general model for analyzing such a shared-channel, multi- hop, WDM network. Our analysis yields a counterintuitive result: it is sometimes better to employ fewer channels than a larger number of cha nnels. We explore bounds on the ranges of w which admit queueing stabi lity-using too few or too many channels can lead to instability. We al so obtain an estimate for the optimal number of channels that minimize s network-wide queueing delay.