PTX5000 Cooling System

Fan Trays

The PTX5000 cooling system components work together to keep all components within the acceptable temperature range. If the maximum temperature specification is exceeded and the system cannot be adequately cooled, the Routing Engine shuts down some or all of the hardware components. If a fan fails or the temperature rises above the temperature thresholds, the speed of the remaining fans in the zone is automatically adjusted to keep the temperature within the acceptable range.

All fan trays are hot-insertable and hot-removable.

The cooling system contains the following fan trays:

• Cooling zone 0—One vertical fan tray (Fan Tray 0) with fourteen fans cools the following components installed in the rear card cage: Routing Engines, Control Boards, and SIBs. The vertical fan tray is not interchangeable with the horizontal fan trays. The fans in the Fan Tray 0 are set to a default speed of 21% of maximum speed.

  Figure 1: Vertical Fan Tray

• Cooling zone 1—The upper Fan Tray 1 and lower Fan Tray 2 horizontal fan trays, each of which contain six fans, cool the components installed in the front card cage (FPCs and PICs), and the CCGs. Both horizontal fan trays are interchangeable with each other.

  Cooling zone 1 has two sections:

  • Cooling zone 1 section 1 cools FPCs 0 through 4.

  • Cooling zone 1 section 2 cools FPCs 3 through 7.

    Note:

    FPCs 3 and 4 can be cooled by either cooling zone 1 section.

  When FPCs are installed in a section, the software sets the fan speeds according to the temperature. When no FPCs are installed in cooling zone 1 section 1, the left fans in the horizontal fan trays in cooling zone 1 are set to 34% of maximum speed. When no FPCs are installed in cooling zone 1 section 2, the right fans in the horizontal fan trays in cooling zone 1 are set to 34% of maximum speed.

  Figure 2: FAN-PTX-H Horizontal Fan Tray
  Figure 3: FAN3-PTX-H Horizontal Fan Tray

Airflow

Figure 4 shows the airflow through the PTX5000.

Figure 4: Airflow Through the Chassis

Air Filters

The cooling system contains three air filters:

• One air filter is located inside the vertical fan tray (Figure 5).

  Figure 5: Vertical Fan Tray Air Filter

• One air filter is located below the lower horizontal fan tray (Figure 6).

  Figure 6: Horizontal Fan Tray Air Filter

• One air filter is located inside the door for the power supply modules (Figure 7).

  Figure 7: PSM Door Air Filter

All air filters are hot-insertable and hot-removable.

Power Supplies

Each DC power supply module contains two fans that cools that PSM. The power distribution units are also cooled by the fans in the PSMs.