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M320 Cooling System Description


The cooling system consists of the following components:

  • Two front fan trays

  • Front air filter

  • Rear fan tray

  • Rear air filter

The cooling system components work together to keep all router components within the acceptable temperature range (see Figure 1). All fan trays and filters are hot-insertable and hot-removable. The two front fan trays are interchangeable. The front and rear fan trays are not interchangeable.

Figure 1: Airflow Through the Chassis
Airflow Through the Chassis

The host subsystem monitors the temperature of the router components. When the router is operating normally, the fans function at lower than full speed. If a fan fails or the ambient temperature rises above a threshold, the speed of the remaining fans is automatically adjusted to keep the temperature within the acceptable range. If the ambient maximum temperature specification is exceeded and the system cannot be adequately cooled, the Routing Engine shuts down some or all of the hardware components.