Mining the Rings: Strategies for Ring-to-Mesh Evolution

We assess the scope for serving ongoing growth in transport demand while deferring or eliminating expenditure for additional capacity by reclaiming the protection capacity and inefficiently used working capacity in existing rings. Reclamation is through re-design of the routing and restoration in the network using mesh principles within the pre-existing ring capacities. The installed working and protection capacity of existing rings is viewed as a sunk investment, an existing resource, to be “mined” and incorporated into a mesh-operated network that serves both existing and ongoing growth. Three ways of approaching the idea are given. The last is a detailed planning model for minimum cost evolution out to a given total growth multiplier that considers the costs of new mesh capacity additions, nodal costs for mesh access to existing ring capacity and selective ADM conversions and re-use decisions. Depending on the type of initial ring network design results show that in some cases a complete doubling or even tripling of demand could be supported with little or no additional capacity investment through the period of ring-to-mesh conversion by ring-mining. The strategy may mean that an operator that could handle the administrative process of conversion could access the opportunity to grow their business for a year or more without capital additions for transport capacity. This re-capture of existing installed protection capacity for conversion to service-bearing use would be a one time business strategy opportunity made possible by a ring mining conversion from ring to mesh.