Dual-Fiber-Link OBS for Metropolitan Area Networks: Modelling, Analysis and Performance Evaluation

In metropolitan area networks (MANs), fiber optic rings are widely deployed. These rings are currently using architectures that are neither optimized nor scalable to the network demands. Therefore, some emerging technologies are being pushed to replace the traditional architecture. Optical burst switching (OBS) is an effective and promising optical switching technology among these emerging technologies. In this paper, a new architecture, called dual-fiber-link OBS and a related media access control protocol, are proposed for MANs. The proposed architecture, which uses dual-fiber link to ease burst contention, has the similar functions of fiber delay lines, partial wavelength conversion, and deflection routing. A theoretical model is developed for evaluating the performance of the proposed architecture. Furthermore, the dual-fiber-link is compared with the single-fiber link and the simple two-fiber link schemes by introduced them into ring and mesh MANs through simulations. Both analysis and simulation results show that the DFL OBS MANs is feasible for carrying out with existing commercial devices and available dark fibers. It is commercially viable in that the DFL can exponentially decrease the burst dropping probability in the ring and mesh MANs.