Abstract: A packet switch comprises a switch having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with routing information attached to each packet, a plurality of pairs of input/output lines connected to terminals or other switches, a plurality of line interface provided one for each of the input/output lines and each connected to one of the input lines and one of the output lines of the switch, and a controller connected to one of the input lines and one of the output lines of the switch. Control information is communicated between the controller and the line interfaces or the switch via a control packet through the switch. The switch may be a plurality of multi-stage connected unit switches and input lines and output lines thereof are divided into a plurality of groups.