A high capacity packet switch is implemented using an expansion module that divides an incoming packet cell into a plurality of segments and supplies the segments, based on their sequential order, to respective ones of a plurality of concentrator units contained in the expansion module. Each concentrator unit includes a plurality of concentrator logic units and one of those logic units accepts a segment for storage based on routing information contained in the packet cell. The stored segments forming a packet cell are thereafter unloaded and recombined in proper sequence for routing to a packet switch module, which then forwards the packet cell toward its destination.