A modular network switch is disclosed. In an embodiment, removable interface modules and a switch circuit board (SMB) are housed in a chassis. Each of the interface modules includes a circuit board that is positioned in parallel with other interface modules. The SMB is oriented in a plane perpendicular to orientation planes of the interface modules, and the circuit boards are connected to the switch circuit board. A switch chip is electrically connected to SMB, and configured to switch network traffic between network connections of the interface modules. The chassis may include airflow regions separated by a divider with respective air intake vents. A power supply is housed in one of the regions and the SMB/interface modules are housed in another region. Power supplies provide power to the interface modules via a bus bar and provide power to the switch circuit board via a connection separate from the bus bar.