Some studies on the architectural aspects of next-generation optical networks

This paper deals with a proposed layered architecture for third generation lightwave networks, also known as all-optical networks (AON). In AONs, a path between the end-to-end nodes remains entirely optical. These paths are called lightpaths. In the proposed layered structure for AONs, each layer communicates with its peer through protocol data units (PDUs). Service data units are being used by each layer for communicating with its neighbour in the protocol stack. The SDUs are not visible but can be conceived to be flowing in the vertical direction in the protocol stack. The optical layer lies in between physical layer and data link layer. The differences of the AON architecture from the traditional protocol layers are highlighted with a view to emphasise the importance of a new optical layer between the physical and data link (or ATM) layers. Moreover, network control and management will play a significant role in this proposed model.