A Low Cost and Effective Link Protection Approach for Enhanced Survivability in Optical Transport Networks

A well-recognized problem in high-speed all-optical networks is that fibres and switches frequently fail. When a network, designed in a non-robust way, encounters such kind of problem it can become highly vulnerable, i.e. experiencing large fractions of connections disruption. This makes resiliency a key issue in network design and thus efficient protection schemas are needed so that when a failure occurs, the involved traffic must be immediately rerouted over a predetermined backup path without affecting the user-perceivable service quality. In this paper we propose a new protection scheme, achieving robustness through a new low complexity link protection algorithm, which can be used to select end-to-end totally disjoint backup paths between each couple of nodes in a mesh network, providing restoration speeds comparable to ring restoration. Many research efforts in this area are targeted at optimization, with the objective of using as much capacity as possible while trying to guarantee adequate levels of protection. The design requirements for our scheme were instead simplicity and performance, aiming at providing a way of quickly computing backup paths for each link without taking resource optimization issues into consideration. We believe that the novel formulations and results of this paper, may be of interest for a network operator wishing to improve connections reliability, at a low implementation cost.