Leaf-spine architecture for OTN switching

The application of a leaf-spine switching architecture is considered for Layer 1 circuit switching, such as with OTN ODU-based switching. Simple relationships are derived for the achievable leaf-spine switch capacity and scalability, given the number and capacity of individual leaf and spine switch elements, and bandwidth for leaf-spine interlinks. Considerations for optimizing cost with respect to the partitioning of leaf and spine switch elements and fabric interlink bandwidth are analyzed and discussed, along with considerations for protection against equipment failures. Simulation results are then provided for different leaf-spine configurations and switching degrees.