Traffic management in photonic packet switching nodes by priority assignment and selective discarding

Abstract

Photonic packet switching faces a major challenge in providing low packet loss probability under the constraint of shallow optical buffer depth. Although improvements have been gained by exploiting the wavelength domain through the use of WDM and wavelength conversion, performance enhancement through the use of packet priorities have yet to be investigated. This paper discusses the relationship between the inter-networking unit, optical buffering, and node control necessary to apply a reactive method of traffic management to an optical packet switching node. Analytical models, supported by simulations, for the performance of photonic switching nodes supporting packets with two levels of priority are presented. Nodes with and without optical buffers are considered. Buffer sharing among packets with different priorities backed by an early-discard mechanism is studied. The possibility of matching resource to traffic type is introduced, enabling node architectures to be designed using fewer buffers and wavelengths through optical differentiated services.