On the impact of transmission technologies in metropolitan networks

Current metro networks are deployed using IP/MPLS equipment on top of ring physical topologies. Such networks are migrating from 10G interfaces to 100G. Such evolution must consider not only the packet layer, but also the underlying infrastructure with its limitations. This paper assesses alternative deployments to upgrade metro networks in terms of cost efficiency. For scenarios with low traffic profiles, operators use dark fiber and grey interfaces in the packet equipment. However, transmission techniques helps to reduce the utilization of the fiber pairs. Results demonstrate that the cost of the fiber infrastructure greatly conditions the deployments. Based on the cost relation between 10G and 100G, it is more efficient to maintain the network in 10G technologies. However, the technical limitations on the metro equipment as well as the operational complexity justifies the migration to 100G.