Arrangement for providing linearly scaleable address forwarding tables within multiple network switch modules

1. Field of the Invention A network switching system having a plurality of multiport switch modules arranged in a cascaded sequence uses a signaling protocol that eliminates the necessity of storing a given network address within each of the address forwarding tables of the multiport switch modules. A network switch module, having an address forwarding table for storing switching information for respective stored network addresses and that receives a data packet, outputs a switching request to a subsequent one of the switch modules based on a determined absence of the destination address of the received data packet in the address forwarding table. Each of the successive network switch modules passes the switching request to the next switch module in the sequence upon a determined absence of the destination address in the corresponding address forwarding table. The switching request identifies the originating network switch module having received the data packet, enabling the network switch module having the last position in the cascaded sequence relative to the originating network switch module to generate a flood signal to all the network switch modules if none of the network switch modules have the destination address in their respective address forwarding tables. Hence, the multiport switch modules can be arranged in a cascaded sequence to provide increased port density, without the necessity of unnecessarily populating the address forwarding tables with each and every network address detected by any one of the network switch modules.