Juniper M Series Monitoring And Troubleshooting Manual page 379

Related
Documentation
TX Matrix Router Cooling System
Copyright © 2012, Juniper Networks, Inc.
Checklist for Monitoring the Cooling System on page 317
The cooling system contains the following components:
Two front fan trays—The front fan trays each contains 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).
Rear fan tray—The rear fan tray contains eight fans and is not interchangeable with
the front trays. It cools the components installed in the rear card cage (the Routing
Engines and TX-CBs).
Front and rear air filter—Air filters for both the front and rear fan trays help keep dust
and other particles from entering the cooling system.
Power supply fans—The power supplies each has a 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 TX-CB
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.
Figure 177 on page 336 shows the cooling system components in TX Matrix routers.
Chapter 11: Monitoring the Cooling System
335