Constraint-Based Local Search for Finding Node-Disjoint Bounded-Paths in Optical Access Networks

Mass deployment of fibre access networks is without doubt one of the goals of many network operators around the globe. The Passive Optical Network has been proposed as a solution to help deliver mass deployment of fibre-to-the-home (FTTH), by reducing the cost per customer compared to current commercially available technologies. A major failure in the access network (e.g., fibre cut, amplifier failure, or other equipment can fail) might affect tens of thousands of customers. Therefore, protecting the network from such failures is one of the most important requirements in the deployment of FTTH solutions. In this paper we use a constraint-based local search approach to design reliable passive optical networks via node-disjoint paths whereby each customer is protected against any one node or link failure. We experiment with a set of very large size real-world networks corresponding to Ireland, Italy and the UK and demonstrate the tradeoff between cost and resiliency.