A novel collision free WDM optical switching network

To avoid burst collision in OBS-WDM ring network, a novel scheme called Estimated Traffic based Longest Queue First (ETLQF) has been proposed. In it, the scheduler considers both the queue length and the incoming traffic. The scheduler can adjust the queue lengths in advance to cater to the incoming traffic, targeting to reduce cell loss ratio (CLR) and improve the buffer utilization. The simulation results show that the ETLQF in OBS ring networks not only reduces CLR by 10–60%, but also achieves high throughput while saving 65% of wavelengths, when compared to conventional schemes with only destination delay.