Recursive concentrator structure with applications to self-routing switching networks

A technique for constructing an N-input concentrator from two (N/ 2)-input concentrators and a stage of 2×2 switching elements is described. Recursive decomposition of each of the (N/2)-input concentrators yields a log2N-stage witching network similar in topology to the inverse omega network. The control algorithm for setting the switching elements is shown to be a simple logic function of the activity bits of the inputs. An iterative cell that combines the functions of the control logic and the 2×2 switching element can be used as a building block to realize the entire concentrator. Applications of the concentrator structure as an interconnection fabric in fast packet switching is explored. This leads to an efficient self-routing network, similar in topology to the transposed Batcher-banyan network.