Physical Topology Design for All-Optical Networks

There are many advantages of deploying an all- optical network. Unfortunately, there are still few guidelines on how to properly design the physical topology for such a network. We propose an efficient physical topology design algorithm and we use the asymptotic growth rate of the provisioned capacity as a metric to compare various design alternatives. A higher asymptotic growth rate translates directly into higher deployment cost for large networks. Our study shows that taking fiber length into consideration can lead to lower capacity requirement. We also find that a sufficiently large fiber-to-node ratio is necessary in order to minimize the asymptotic growth in the provisioned capacity, increase capacity utilization and minimize the need for wavelength conversion. We study a real network and find that its fiber-to-node ratio is too low. As a result, large provisioned capacity is required and less than 55% of the capacity is usable. By increasing the ratio, we can reduce the provisioned capacity and achieve close to 80% utilization.