Cooling System and Airflow in an EX4200 Switch

The cooling system in an EX4200 switch consists of a field-replaceable unit (FRU) fan tray with three fans (see Figure 1). The fan tray is located at the rear of the chassis and provides side-to-rear chassis cooling (see Figure 2).

Figure 1: Fan Tray Used in an EX4200 Switch

Figure 2: Airflow Through the EX4200 Switch Chassis

The fan tray used in an EX4200 switch comes with load-sharing redundancy that can tolerate a single fan failure at room temperature (below 45° C/113° F) to still provide sufficient cooling.

Temperature sensors in the chassis monitor the temperature within the chassis. The system raises an alarm if the fan fails or if the temperature inside the chassis rises above permitted levels. If the temperature inside the chassis rises above the threshold, the system shuts down automatically and the temperature shutdown LED on the rear panel is lit. You can see the status of fans and the temperature from the Show Environment Status option in the Status menu in the LCD panel.