The nodal processor module (NPM) is a 68040 microprocessor-based system controller that runs the software for controlling the IGX switch. The NPM communicates with the other system cards over the control bus.The NPM performs the following major functions: runs the software for controlling, configuring, diagnosing, and monitoring the IGX switch; sends configuration and control commands over the control bus to other cards in the switch; receives statistics, status, and alarm messages from the other cards in the switch; generates all system bus control signals for directing the interpretation of address buses and controlling data transfers; communicates with other nodes in the network.The NPM communicates with all other nodes through a trunk that uses a reserved queue on the trunk. The NPM communication link with other nodes carries information about new connections, topology changes, and rerouting.