Optimal scheduling algorithms in WDM optical passive star networks

Abstract

All-to-all broadcast scheduling problems are considered in WDM optical passive star networks where k wavelengths are available in the network. It is assumed that each node has exactly one tunable transmitter and one fixed tuned receiver. All transmitters can tune to k different wavelengths, and have the same tuning delay δ to tune from one wavelength to another. In this paper, we take δ to be a nonnegative integer which can be expressed in units of packet durations. When all-to-all broadcasts are scheduled periodically in the network, the lower bounds are established on the minimum cycle length depending on whether each node sends packets to itself or not. And then, we present optimal scheduling algorithms in both cases for arbitrary number of wavelengths and for arbitrary value of the tuning delay.