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TX Matrix Cooling System Description


Cooling System Description

The cooling system components work together to keep all TX Matrix router components within the acceptable temperature range (see Figure 1). 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.

Figure 1: Airflow Through the Chassis
Airflow Through the Chassis

To function properly, the entire cooling system requires an unobstructed airflow and proper clearance around the site, as described in TX Matrix Clearance Requirements for Airflow and Hardware Maintenance.

The cooling system consists of the following components:

  • Two front fan trays

  • Rear fan tray

  • Front air filter

  • Rear air filter

Fan Tray Description

The TX Matrix router cooling system contains two front and one rear fan tray (see Front View of the TX Matrix Router and Rear View of the TX Matrix Router). The fan trays each contain multiple fans that work in unison to cool the TX Matrix router components. The fan trays are hot-insertable and hot-removable. Figure 1 shows the airflow through the TX Matrix router.

  • The front fan trays each contain six fans and are interchangeable with each other. The front fan trays cool the components installed in the front card cage (the TX-SIBs, TX-CIPs, and midplane).

  • The rear fan tray contains eight fans and is not interchangeable with the front trays. The rear fan tray cools the components installed in the rear card cage (the Routing Engines and Control Boards).

  • Each power supply has one fan that cools that power supply.

When the TX Matrix router is operating normally, the fans function at lower than full speed. The host subsystem constantly monitors the temperature detected by sensors on the midplane and TX Matrix router components. If a fan fails or the ambient temperature rises above a threshold, the host subsystem adjusts the speed of the remaining fans to maintain proper cooling and keep the temperature within the acceptable range. If the TX Matrix router temperature exceeds the acceptable maximum, the Control Board turns off the power supplies. A red alarm is triggered when a fan fails, and a yellow alarm is triggered when a fan tray is removed.


To maintain proper cooling, do not operate the TX Matrix router with the rear fan tray removed for more than 1 minute.

Air Filter Description

Air filters for both the front and rear fan trays help keep dust and other particles from entering the cooling system. The TX Matrix router has one front air filter and one rear air filter. The air filter is hot-insertable and hot-removable.