Efficient scheduling algorithms for real-time service on WDM optical networks

One of the important issues in the design of future generation high-speed n etworks is the provision of real-time services to different types of traffi c with various time constraints. In this paper we study the problem of prov iding real-time service to hard and soft real-time messages in Wavelength-D ivision-Multiplexing (WDM) optical networks. We propose a set of scheduling algorithms which prioritize and manage message transmissions in single-hop WDM passive star networks based on specific message time constraints. In p articular, we develop time-based priority schemes for scheduling message tr ansmissions in order to increase the real-time performance of a WDM network topology. We formulated an analytical model and conducted extensive discre te-event simulations to evaluate the performance of the proposed algorithms . We compared their performances with that of the state-of-the-art WDM sche duling algorithms which typically do not consider the time constraint of th e transmitted messages. This study suggests that when scheduling real-time messages in WDM networks, one has to consider not only the problem of resou rces allocation in the network but also the problem of sequencing messages based on their time constraints.