A Traffic Management Framework for Optical Routers with Small Buffers

The scarcity of buffering within all-optical routers poses a significant challenge to their potential deployment in the Internet back bone. In this paper, we present a thorough investigation into the performance of IRIS (Integrated Router Interconnected Spectrally), an all-optical router, using network and traffic models representative of the Internet back bone. When exposed to the burstiness of Internet traffic, optical routers are susceptible to significant losses, even under light load conditions. We evaluate a rate control framework that uses electronic-based edge routers to control the rate and to shape the traffic entering the all-optical core. Our results from simulations show that IRIS can operate loss free at utilizations as high as 90 percent, and that the severity of such losses beyond the 90 percent threshold can be greatly reduced with a slight increase in buffer size. Lastly, we show that the reordering introduced by the load-balanced architecture of IRIS has almost no impact on the end-to-end packet ordering.