Sorting unit for a switching node comprising a plurality of digital switching matrix networks for fast, asynchronous packet switching networks

A sorting unit for a switching node comprising a plurality of digital switching matrix networks for fast, asynchronous packet switching networks, said switching node comprising a multi-stage, mixed connecting structure in accord with a banyan tree structure, that forms a complete trunk group in which every input of the switching node is connectable to every output thereof, characterized in that

• said digital switching matrix networks comprise a plurality of self-controlling and self-routing sorting units that are a multi-stage circuit switching arrangement comprising a rectangular array of beta elements (.beta.) with m rows and 2m-1 columns, where 2m is equal to the number of inputs and is also equal to the number of outputs of the sorting unit and m is a power of two;
• each said sorting unit is divided into a first sub-unit acting as distributor unit comprising an array of beta elements (.beta.) with m columns, and a second sub-unit acting as a correction unit comprising an array with m-1 columns of beta elements (.beta.);
• said sub-units each composed of m smallest units, each said smallest unit respectively containing four beta elements, of which two beta elements form one input pair and two beta elements form one output pair, said pairs being connected to one another such that every input of said input pair of connectable to every output of said output pair;
• two first ones of said smallest units forming an input unit pair and two second ones of said smallest units forming an output unit pair, whereby said units are in turn connected such to one another that each of the inputs of an input unit pair is connectable to each of the outputs of an output unit pair;
• and
• means for connecting the outputs of the last (2m-1.sup.th) column of said correction unit to a following group of switching matrix networks of the switching node.