Contention avoidance in bufferless slotted optical packet switched networks with egress switch coordination

Optical packets contention in optical packet switched (OPS) networks can lead to Optical packet loss which will reduce network performance. In this paper, a new contention avoidance technique is proposed which utilizes the combination of traffic shaping at ingress switches and a time slot reservation technique using the coordination of egress switches. This novel protocol is called egress coordination OPS (EGCOPS) suitable for buffer-less slotted-OPS networks. Simulation results show that the EGCOPS outperforms the original slotted-OPS protocol in terms of optical packet loss rate (PLR), with or without using wavelength conversion. However, the packet shaping feature of EGCOPS can increase the delay of users' packets at the queues of ingress switches. There is a trade-off between the PLR improvement and the additional delay applied to the users' packets. Still, EGCOPS parameters can be selected in such a way that additional delay can be tolerable by users' applications.