Analysis of fibre-loop optical buffers with a void-avoiding schedule

Abstract

In optical packet/burst switching, fibre-loop optical buffers provide a compact and effective means of contention resolution. In case of fixed packet length, the involved loop length is typically chosen matched (equal to the packet length), and the loops are arranged in parallel, constituting a single-stage buffer. In this contribution, we investigate the performance of such a buffer in an asynchronous network setting, assuming batch-Poisson arrivals and assuming a so-called void-avoiding schedule. We show that by timediscretisation, the fibre-loop dynamics can be captured by a particular type of exhaustive polling model. We obtain performance measures such as the moments of the optical queue content and packet delay for the discretised model as well as for the asynchronous optical buffer. We illustrate our approach by various numerical examples.

Selective void creation/filling for variable size packets and multiple wavelengths

“…The best solution to avoid conversion is the combined use of wavelength conversion and Fiber Delay Lines (FDLs) [2]. In these FDLs, packets that need to be buffered are sent through sufficiently long pieces of coiled fiber to delay them for the time needed [11,1]. Additionally with the use of wavelength converters (WCs) packets can be converted to a different wavelength thereby also avoiding contention.…”