Banyan switch

It is named for its resemblance to the roots of the banyan tree which cross over in complex patterns.

They can be mechanical microelectromechanical systems, electrical or nonlinear optics.

Typical crossover matrices follow this formula: an N×N banyan switch uses (N/2) log2 N elements.

By connecting these switching elements in series and parallel it is possible therefore, to route packets in more complicated ways depending on the desired routes to establish.

The future is moving to larger arrays of inputs and outputs needed in a very small space.