A novel medium access control protocol for optical local networks based on data request ordering

The basic aim of the scheduling algorithms in wavelength division multiplexing (WDM) single-hop optical networks is to construct a short schedule, in order to support quick communication between the nodes of the network. A design of medium access control (MAC) protocol without collisions is introduced for scheduling variable-length data packets based on a broadcast and select architecture. The system includes only data channels and the coordination of the transmissions is achieved via control packets, functioning before the beginning of actual transmissions. The proposed scheme adopts a prediction mechanism in order to eliminate the possible delay introduced by the scheduling computation between the control and data phases of each cycle of transmission. The two common scheduling strategies suggested try to reorder the service sequence of the nodes, by prioritizing the nodes with long data packets, compared with the nodes with short data packets. The final schedule, formed by a scheduling matrix, seems to be much shorter and leads to an increase, in terms of channel utilization. The extensive simulation results show that the novel scheduling techniques offer more free time space for schedule and allow more data to travel on the medium for the same amount of time. Also, the mean packet delay on the queues is reduced and the relation throughput-delay is much better. r 2007 Elsevier Ltd. All rights reserved.