Architectural principles of optical regional and metropolitan access networks

High-end access networks that serve large businesses and campuses will greatly benefit from the introduction of WDM technology, in terms of greater bandwidth, increased flexibility, and enhanced services. We refer to such networks as optical regional and metropolitan access networks (ORMA-Nets). Here, we qualitatively and quantitatively investigate many important principles, as well as challenges, in deploying ORMA-Nets. Access networks in general are functionally comprised of a feeder network, which is responsible for traffic aggregation, and a distribution network, which directly interfaces with the customer premises. We present several configurable, scalable designs for the feeder network that are capable of aggregating a range of traffic types and rates. We also present architectures for achieving a high degree of functionality using relatively low-cost, passive optical components in the distribution network. We explore topics such as optimal switch placement and wavelength banding, and emphasize the technologies that are needed to deliver advanced capabilities. Various underlying themes run throughout the paper, such as optionally not always using bandwidth as efficiently as possible in order to simplify the architecture, and the importance of transparency in providing enhanced services and architectural flexibility.