Availability Analysis of Meta-Mesh Restorable Transport Networks

Abstract

The span-restorable meta-mesh approach was previously proposed as a novel method for improving the capacity efficiency of span restoration in a sparse network. The fundamental idea behind this method is to route lightpaths that fully transit chains of degree-2 nodes onto logical bypass spans that physically traverse the chain, but which are allowed to fail back to the anchor nodes of the chain. From the perspective of transiting lightpaths, the result is an increase in network connectivity. Previous work on the meta-mesh design considered only single-failure restorability. The work herein addresses the issue of meta-mesh dual-failure survivability by developing and evaluating two new ILP design models. The first model provides the minimum total cost to design a meta-mesh network capable of withstanding all possible dual span failures scenarios. The second model provides a maximization of the dual failure restorability by minimizing the number of non-restored working capacities with a given limit on total spare capacity investment. In addition, this work investigates an improvement of the prior meta-mesh design by allowing the existence of a logical bypass span in low priority chains in the network. Experiments are performed on six master test-case networks of various topologies and scales.