IMPROVED METRO NETWORK DESIGN BY GROOMING AND AGGREGATION OF STS-1 DEMANDS INTO OC-192/OC-48 LIGHTPATHS

摘要

A new design method was developed to optimize WDM metropolitan optical networks. We pre-processed the demand data to create well-utilized lightpaths, building direct lightpaths when the demand warranted it. For the remainder of the demand, we aggregated demand by imposing a clustering on the network. We funneled the demand through the hub nodes designated for each cluster, but groomed to minimize the number of hops whenever possible. Our results show that it is important to cluster, but the exact details of the clustering are not as important. Specific equipment capabilities and limitations, as well as practical implementation criteria, will affect the number of clusters. This pre-processed demand data was then fed to a commercial WDM ring design tool to produce designs that were more cost-effective than the tool could produce when working from the original, un-processed demand data. Our optimized WDM design was based on explicit aggregation to wavelengths to maximize economy of scale and a grooming algorithm that minimizes the number of hops, and thus the number of grooming interfaces (e.g., ADMs, grooming OXC ports). This grooming/aggregation design leverages WDM to reduce expensive electronics, and demonstrates the utility of metropolitan WDM beyond fiber exhaust. Furthermore, metro networks similar to the one studied will have both DWDM and SONET systems. The traffic patterns, type, and quantity of demand will dictate the relative number of NGSONET and DWDM systems used. Metropolitan WDM networks based on methods developed in this study show improvement on equipment first cost and also provide lower cost for growth and support emerging non-TDM and wavelength services.