The cooling system in an QFX5100 device consists of fan modules and a single fan in each power supply. The number
of fan modules vary depending whether the size of the switch is 1 U or 2 U high. All switches can be set up to work in
one of two airflow directions:
Airflow In–Air comes into the switch through the vents in the field-replaceable units (FRUs)
Airflow Out–Air comes into the switch through the vents in the port panel.