Performance modeling of optical buffers supporting variable length packets

We propose an analytic method to modeling the queuing performance of optical buffer consisting of a number of fiber delay lines (FDL). We present a detailed analysis of the loss and delay performance in an optical buffer having access to a single output channel. Optical buffer differs significantly from conventional electronic buffer in that only a discrete set of delays can be realized for contention resolution. This leads to excess load and prolongs the delay experienced by the packets, which degrade the overall performance. Our analytical model provides the closed-form expressions of the packet blocking probability and mean delay, which enable us to explore the trade-off between buffer performance and design parameters such as the number of the FDLs, the time granularity of the FDLs, and evaluate the impact of design parameters to the overall queuing performance. Simulation results match well with our analytical prediction and show the accuracy of our method.