An adaptive scheduling algorithm for differentiated services on WDM optical networks

One of the important issues in the design of future generation high-speed networks is to provide differentiated services to different types of applications with various time constraints. In this paper, we study the problem of providing real-time service to either hard or soft real-time messages in conjunction with a normal transmission service to variable-length messages without time constraints in Wavelength-Division-Multiplexing (WDM) optical networks. We propose an adaptive scheduling algorithm to schedule and manage message transmissions in single-hop passive-star coupler based WDM optical networks. We have analyzed the complexity of the algorithm to show its feasibility. In addition, we have conducted extensive discrete-event simulations to evaluate the performance of the proposed algorithm. This study suggests that when scheduling message transmission in WDM networks, a differentiated service should be designed to benefit the transmission of both real-time and non-real-time messages so that the overall performance of the network could be improved. (C) 2004 Elsevier B.V. All rights reserved.