Buffering Light: Achilles’ Heel of the Next-Generation Backbone Network

How is current Internet infrastructure to cope with everincreasing bandwidth demands? Adding capacity to the present electronically switched network is common practice, and offers inexpensive but only temporary (bandwidth famine) relief. In the long run, it will become a necessity to rethink the technology itself. Moving to optical switching is the most viable option, but has a snake in the grass: optical buffering. Recent performance results point out that an optical buffer can never match a RAM buffer. Nevertheless, a delicate tuning of the design parameters can reduce the performance gap between the two tremendously. The tuning of the design parameters is the focus of my research. By means of probabilities, we at TELIN have developed several analytic models that capture the interaction between traffic, hardware parameters and performance. Since these analytical models have (extremely) low numerical complexity, and high robustness, they provide an essential tool for optical switch design. Keywords—fiber delay lines; optical buffers; stochastic modelling