An Efficient Clustering Oriented Algorithm for Message Scheduling on WDM Star Networks

Message sequencing and channel assignment are two important issues that have to be addressed when designing MAC protocols for optical Wavelength division multiplexing (WDM) networks. Up to now, popular approaches deal with channel assignment without however addressing the order in which the messages are scheduled. This paper presents a new reservation-based message scheduling algorithm for WDM star networks which is based on clustering techniques. The proposed clustering oriented-earliest available time scheduling (CO-EATS) creates groups of nodes whose messages are destined to common destination nodes. The goal of CO-EATS is to prevent consecutive messages from being destined to the same node. The simulation results have shown that the proposed scheme improves channel utilization and as a result it leads to higher network throughput while it keeps mean packet delay at low levels in comparison with conventional scheduling algorithms.