Architectural principles of optical regional and metropolitan access networks

High-end access networks that serve large businesses and campuses will grea tly benefit from the introduction of WDM technology, in terms of greater ba ndwidth, increased flexibility, and enhanced services. We refer to such net works as optical regional and metropolitan access networks (ORMA-Nets), Her e, we qualitatively and quantitatively investigate many important principle s, as well as challenges, in deploying ORMA-Nets. Access networks in genera l 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 desig ns for the feeder network that are capable of aggregating a range of traffi c types and rates. We also present architectures for achieving a high degre e of functionality using relatively low-cost, passive optical components in the distribution network, We explore topics such as optimal switch placeme nt and wavelength banding, and emphasize the technologies that are needed t o deliver advanced capabilities. Various underlying themes run throughout t he paper, such as optionally not always using bandwidth as efficiently as p ossible in order to simplify the architecture, and the importance of transp arency in providing enhanced services and architectural flexibility.