Combined WDM and SONET Network Design

This paper considers grooming of low speed traf-c into high speed lightpaths in a WDM based optical ring with a primary goal of reducing the cost of the entire system, which is dominated by the cost of the SONET transmission equipment connected to the optical ring. The paper attempts to enumerate the architectural options provided by SONET to arrive at a cost-eeective solution, including UPSR and BLSR rings, use of back-to-back connections between SONET ADMs to reduce the overall cost, and use of diierent ring speeds (OC-48 and OC-12). To demonstrate each of the architectures, a uniform traac is considered and its grooming and resulting SONET architecture demonstrated. The paper deviates from earlier approaches which break the problem into two steps: traac grooming and assignment of lightpaths to rings, in that it looks at the problem as a whole and tries to solve it in a single step. The paper also considers the characteristics of SONET UPSR and BLSR rings and how these aaect the grooming. The paper derives lower and upper bounds to these problems for uniform traac and shows how these improve on known results.