Maintaining the MX2020 Cooling System Components

Purpose

For optimum cooling, verify the condition of the air vents. Dust can clog air vents, reducing cooling system efficiency.

Action

On a regular basis, check the vents and clean them as necessary.

Purpose

For optimum cooling, verify the condition of the air filter.

Action

• Regularly inspect the air filter. A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis. The filter degrades over time. You must replace the filter every 6 months.

  CAUTION:

  Always keep the air filter in place while the router is operating. Because the fans are very powerful, they could pull small bits of wire or other materials into the router through the unfiltered air intake. This could damage the router components.

• The shelf life of polyurethane filter varies from two years to five years depending on the storage conditions. Store in a cool, dry, and dark environment. Wrap the media in plastic and store in an environment with relative humidity between 40%- 80% and temperature between 40°F (4° C) to 90°F (32° C). Note that if the material flakes, or becomes brittle when rubbed or deformed, it is no longer usable.

Purpose

For optimum cooling, visually inspect the condition of the air baffle. See (Figure 1 and Figure 2).

Action

• Inspect the air baffle with adjustable louvers regularly to determine if they are set to a 10-degree upward tilt/angle to direct the exhaust air away from the router.

Figure 1: Air Baffle - Fixed Louvers

Figure 2: Air Baffle - Adjustable Louvers

Purpose

For optimum cooling, verify the condition of the fans.

Action

• Monitor the status of the fans. The fan trays each contain multiple fans that work in unison to cool the router components. If one fan fails, the host subsystem adjusts the speed of the remaining fans to maintain proper cooling. A red alarm is triggered when a fan fails, and a yellow alarm is triggered when a fan tray is removed. During normal operation, the fans in each fan tray function at normal speed.

• To display the status of the cooling system, issue the show chassis environment command, show chassis environment monitored command, show chassis temperature-thresholds command, or show chassis fan command.

  For the fan trays, the output for the show chassis environment command is similar to the following:

For monitoring the temperature of specific items in the MX2020 router, the output for the show chassis environment monitored command is similar to the following:

For the chassis temperature threshold settings, the output for the show chassis temperature-thresholds command is similar to the following:

For the fan trays, the output for the show chassis fan command is similar to the following:

Fan Tray 0, Fan Tray 1 refer to the lower rear fan trays, Fan Tray 2, and Fan Tray 3 refer to the upper rear fan trays.

Fan 1, Fan 2, Fan 3, Fan 4, Fan 5, and Fan 6 refer to the fans on the fan tray. There are six fans for each fan tray.

Purpose

For optimum router performance, verify the status of the two cooling zones of the chassis. Both Zone 0 and Zone 1 cool the Control Board and Routing Engine (CB-RE). Zone 1 consist of ten MPCs (10 through 19) and their respective MICs, along with the top half of the CB-REs and SFBs. Zone 1 is cooled by fan trays 2 and 3. Zone 0 consists of ten MPCs (0 through 9), and their respective MICs, along with the bottom half of CB-REs and SFBs. Zone 0 is cooled by fan trays 0 and 1. Two fan trays are at the bottom of the chassis, and two fan trays are at the top of the chassis.

Action

On a regular basis:

Check the LEDs on the craft interface for upper and lower fan trays. The green status LEDs labeled 0 and 1, for lower fan trays, and 2 and 3 for the upper fan trays light steadily when a fan tray is functioning normally.

During normal operation:

• The green LEDs next to the fan trays 0, 1, 2, and 3 on the craft interface light steadily when the fan tray is functioning normally for that zone.

• Issue the show chassis zones command to check the status of the two cooling zones. The output is similar to the following: