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Cooling System for PTX Series Packet Transport Routers

The cooling system components work together to keep all components within the acceptable temperature range. The host subsystem monitors the temperature of the components. When the PTX Series Packet Transport 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.

The PTX5000 Packet Transport Router has a cooling system that contains different zones that are monitored and cooled independently.

The cooling system consists of:

  • Fans
  • Different cooling zones
  • Individual monitors and controls for each fan
  • Temperature sensors

Fans are monitored by using CLI commands such as show chassis fan, show chassis environment , and show chassis zones. The command displays the cooling zones, number of fans running, and the temperature of the chassis components. Each horizontal fan tray has 6 fans. The fans run at 30% capacity, instead of 70%, which saves 845 W.

Temperature sensors drive fan speeds. PTX5000 has variable fan speed control for each fan. Fan trays have a wide range of 30-100% of maximum RPM. A wide RPM range allows fans to run at minimum speed, while still enabling an increase in RPM to protect hot components.

Fan trays fail if:

  • Any fan falls below the set RPM
  • Any fan rises above the set RPM
  • Any fan loses power

Cooling Protections

  • Vertical fan tray 0 ramps to 70
  • Horizontal Fan trays 1,2 ramp to 50%
  • After 10 minutes, all fan trays ramp to 100%
  • If the fans cooling the Routing Engine and Control Board are below 50% of the maximum RPM, the Routing Engine and Control Board will shutdown in 15 minutes
  • If a fan fails, all other fans in that cooling zone will ramp to 100%.
 

Related Documentation

 

Published: 2013-07-18

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