To troubleshoot a router, you use the Junos OS command-line
interface (CLI), LCD, alarms, devices connected to the alarm relay
contacts on the CIP, and LEDs on both the components and craft interface.
LEDs—When the Routing Engine detects an alarm condition,
it lights the red or yellow alarm LED on the craft interface as appropriate.
In addition, you can also use the component-specific LEDs on the craft
interface and on the faceplate of a component to troubleshoot the
routing matrix.
LCD—When a red or yellow alarm occurs, the cause
of the alarm messages is displayed on the craft interface LCD. Use
the CLI to display more information about the alarm.
Alarm devices connected to the alarm relay contact on
the CIP—When a red or yellow alarm occurs, it trips the corresponding
alarm relay contact on the CIP.
CLI—The CLI is the primary tool for controlling
and troubleshooting hardware, the Junos OS, routing protocols, and
network connectivity. CLI commands display information from routing
tables, information specific to routing protocols, and information
about network connectivity derived from the ping and traceroute utilities.
For information about using the CLI to troubleshoot the Junos OS,
see the appropriate Junos OS configuration guide.
JTAC—If you need assistance during troubleshooting,
you can contact the Juniper Networks Technical Assistance Center (JTAC)
by using the Web or by telephone. If you encounter software problems,
or problems with hardware components not discussed here, contact JTAC.