The Effects of Tuning Time in Bandwidth-Limited Optical Broadcast Networks

We consider the effects of tuning d e l a y in optical broadcast networks. We show that for offl ine scheduling these effects are small even i f the tuning time is as large as the packet duration. In particular, we consider scheduling of random traffic with tunable transmitters and fixed-tuned receivers. We provide a lower bound to the completaon time of any off-line schedule with an arbitrary number of wavelengths. We then describe a near-optimal schedule which is based on the principle of having idle transmitters tune to wavelengths just-in-time to start their transmissions. Stability and capacity issues in the transmission of real-time traffic are considered. We show that the scheduling problem admits a single stable equilibrium point, and point out how the traffic capacity of a bro'adcast network can be reached. We also consider the implications in connection-oriented networks.