On Control Plane for Service Provisioning in Light-trail WDM Optical Ring Networks

Abstract: A light-trail is a generalized lightpath that enables multiple nodes to statistically share an optical communication path (wavelength bus). A light-trail is different from a lightpath on account of its unique node architecture – that enables formation of unidirectional wavelength buses. A node in a light-trail supports signal flow characteristics of drop-and-continue as well as passive addition leading to formation of the bus. Apart from the node architecture, another differentiation between light-trails and lightpaths is in the use of out-of-band control channel (Optical Supervisory Channel – OSC) for dynamic communication. The combined effect of a unique node architecture and out-of-band control channel enables light-trails to provide capability of sub-wavelength grooming, dynamic provisioning and optical multicasting. These features offered by light-trails are critical for next generation emerging applications such as VoIP, Video-on-demand (VoD), Triple-play and Pseudo-Wire Edge-to-Edge Emulation (PWE3). Current OSC based control channel requires engineering enhancement to provision dynamic and bandwidth efficient services over light-trails. We investigate into the control channel hierarchies in light-trail networks to provision these emerging services. Centralized, distributed, static and dynamic control mechanisms are proposed. Light-trail control for provisioning next generation services is considered through theory and simulation