Abstract

Service providers are showing great interest in deploying mesh architecture in the core of their metropolitan networks because of their inherent advantages and the new capabilities and intelligence of next generation network elements. Previous published work has demonstrated the bandwidth savings of mesh networks over traditionally deployed ring networks. It has also been argued that ring architectures will continue to be deployed in the access and collector portions of the network, with mesh architecture more likely in the IOF core. However, there is no unique single solution for mesh architecture deployment because of different protection schemes choices. These could involve a range of grades of protection that vary from decentralized dedicated (1+1) protection to shared path-based mesh restoration. The challenges faced by the designers are in controlling the capital investment and more importantly in limiting the initial capital costs when deploying a mesh network.

We address these challenges by studying the parameters of a network that influence the implementation of appropriate shared mesh protection schemes, when designing and planning metropolitan area networks. We show that when provisioning for the shared protection capacity in a metropolitan network, it may not always be cost efficient to maximize the sharing and optimize overall network bandwidth usage of the fiber by minimizing the product: "number of wavelengths*fiber length". Instead using simpler node architectures and effective dimensioning, an approach that considers shared-protection routing for single end-to-end demands, may produce a significantly cheaper solution.

We demonstrate our results on a case study of a Major network Service Provider's metropolitan network design, where a low initial capital investment and network growth cost control are the critical issues. The analysis shows that the critical parameters that impact the choice of an appropriate shared mesh scheme are network size, connectivity, traffic load and transparency.

© 2005 Optical Society of America