Chapter 12

Troubleshooting Hardware Components
This chapter describes how to troubleshoot problems with hardware componen ts
installed in the router. If you encounter softwareproblems, or problems with
hardwarecomponents not discussed here, contact the Juniper Networks Technical
Assistance Center (JTAC) as described in “Requesting Support” on page xxiii.
Overview of TroubleshootingResources on page 207
Troubleshootingthe Cooling System on page 212
TroubleshootingPacket Forwarding Engine Components on page213
Troubleshootingthe Power System on page 215

Overview of Troubleshooting Resources

This section provides an overviewof the resources you can use while
troubleshooting problems with the router :
Command-Line Interface on page 207
LEDs on page 208
Chassis and Interface Alarm Messageson page 209
BlownFuseIndicatorsonpage211
Juniper Networks Technical Assistance Center on page 212

Command-Line Interface

The JUNOS Internet softwarecommand-line interface (CLI) is the primary tool for
controlling and troubleshootingrouter hardware, the JUNOS Internet software,
routing protocols, and network connectivity. CLI commands display information
from routing tables,information specific to routing protocols, and information
about network connectivityderived from the ping and traceroute utilities.
You enter CLI commands on one or more externalmanagement devices
connected to the Routing Engine through portson the Connector Interface
Panel (CIP). The port labeled AUXILIARY attachestheRoutingEnginetoalaptop,
modem, or other auxiliary device, the port labeled CONSOLE attaches to a system
Overview of TroubleshootingResources 207