A Di erentiated Optical Services Model for WDM Networks

This article addresses the issues of scalable end-to-end QoS in Metropolitan DWDM networks serving as transit networks for IP access networks. DWDM o ering few wavelengths have in the past been deployed in backbone networks to upgrade point-to-point transmission where sharing is based on coarse granularity. This type of DWDM backbone networks o ering few lightpaths, provides no support for QoS services traversing the network. As DWDM networks with larger numbers of wavelengths penetrate the data-centric Metro environment, speci c IP service requirements such as priority restoration, scalability, dynamic provisioning of capacity and routes, and support for coarse-grain QoS capabilities will have to be addressed in the optical domain in order to achieve end-to-end QoS over a DWDM network. We propose a QoS service model in the optical domain called Di erentiated Optical Services (DoS) based on a set of optical parameters that captures the quality and reliability of the optical lightpath.