As demand for bandwidth keeps increasing, the optical backbone capacity will have to be used more efficiently in future networks. In order to meet this requirement, both optical packet and optical burst switching are proposed as future network techniques. To resolve packet contention in the used optical switches, Fiber Delay Lines and wavelength converters are used to reschedule the contending packets. This rescheduling process is mastered by means of a scheduling algorithm, typically designed for minimal packet loss in case of a finite buffer. Although, depending on the intentions, a wide variety of scheduling algorithms exists, they can be split up in two big categories: void-filling and non-void-filling algorithms. In contrast to the latter, the former allow packets to be scheduled before already scheduled packets, in this way increasing performance but also the computational complexity. In case the packet lengths are fixed and equal to the granularity, the void-filling algorithms behave as non-void-filling algorithms. This is because only voids smaller than the packet length occur, which cannot be filled. We therefore propose an algorithm that selectively creates larger voids, creating voids only when they will likely be filled. Results obtained by Monte Carlo simulation for a single-wavelength buffer show that these algorithms enable significant improvement in both packet loss probability and packet delay. Moreover, based on an intuitive reasoning, an approximation of the threshold controlling void creation is proposed. All this opens opportunities to implement the void creation in more complex settings such as a multi-wavelength buffer.
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