The effects of tuning time in bandwidth-limited optical broadcast networks

We consider the effects of tuning delay in optical broadcast networks. We show that for off-line scheduling these effects are small even if 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 completion 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 broadcast network can be reached. We also consider the implications in connection-oriented networks