Message sequencing techniques for on-line scheduling in WDM networks

Message sequencing and channel assignment are two important issues that need to be addressed in scheduling variable-length messages in a wavelength division multiplexing (WDM) network. Channel assignment addresses the problem of choosing an appropriate data channel via which a message is transmitted to a node. This problem has been addressed extensively in the literature. On the other hand, message sequencing which addresses the order in which messages are sent, has rarely been addressed. We propose a set of scheduling techniques for single-hop WDM passive star networks which address both the sequencing aspect and the assignment aspect of the problem. In particular we develop two priority schemes for sequencing messages in a WDM network in order to increase the overall performance of the network. We evaluate the proposed algorithms, using analytical modeling and discrete-event simulations, by comparing their performance with state-of-the-art scheduling algorithms that only address the assignment problem. We find that significant improvement in performance can be achieved using our scheduling algorithms where message sequencing and channel assignment are simultaneously taken into consideration