How Many Wavelengths Do We Really Need? A Study of the Performance Limits of Packet Over Wavelengths

Coupling Internet protocol (IP) routers with wavelengthselective optical crossconnects makes it possible to extend the existing Internet infrastructure to a wavelength-division–multiplexing optical network. Because optical wavelength routing is transparent to IP, one can achieve very high throughput and low delay when packets are made to bypass the IP forwarding process by being switched directly through the optical crossconnect. We study the performance of a specific instantiation of this approach,which we call packet over wavelengths (POW). We present the POW architecture in detail and discuss its salient features. Realistic simulations of the POW that use actual packet traces in a well-known Internet backbone network reveal the level of performance that can be expected from POW under various options. Specifically, we evaluate the fraction of packets that are switched through the crossconnect as a function of the number of wavelengths and the degree of flow aggregation that can be achieved.Our study, conducted in the context of the veryhigh bandwidth network service (vBNS) Internet backbone, suggests that as few as four wavelengths combined with a high degree of traffic aggregation can carry more than 98% of IP packets in the streamlined switched mode. In cases where it is not possible to aggregate traffic, the deployment of wavelength-merging technology would increase the fraction of IP packets carried in streamlined switched mode by up to 52%. © 2000 SPIE/Baltzer Science Publishers 1388 6916/2000 $15.00 Docu-Bannister 04-03-2000 14:30 Pagina 1