Affiliations: Computer Science Department, University of California, Los Angeles, 3732L Boelter Hall, Los Angeles, CA 90024-1596, USA, [email protected], [email protected]
Note: [] This work was supported by the Defense Advanced Research Projects Agency under Contract MDA 903-87-C0663, Parallel Systems Laboratory.
Abstract: Wavelength division multiple access (WDMA) provides a way to tap the huge bandwidth of an optical fiber by simultaneously operating on multiple channels at different wavelengths, with each channel running at the speed of the electronics of an end user station. This paper presents a mathematical model which approximates WDMA networks with general hardware configurations and arbitrary traffic patterns. Packets which cannot be transmitted upon arrival are blocked (i.e., lost) immediately. We first study the case of a uniform traffic matrix and observe that, when the number of wavelengths is fewer than the number of stations, it is better to have both tunable transmitters and tunable receivers, rather than having only either one of them tunable. Furthermore, we find that only a small number of tunable transmitters and receivers per station is needed to produce performance close to the upper bound. We then construct a general traffic model and propose an iterative solution procedure. A case of hot-spot traffic is studied using this model. We find that adding more resources to the hot-spot node will help improve its performance, but only to a limited extent determined by the traffic imbalance. The match between the model and simulation results are shown to be excellent.
