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Overview of Troubleshooting Resources for the T640 Router


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 router.

  • LCD—When a red or yellow alarm occurs, the cause of the alarm messages is displayed on the craft interface LCD.

  • 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, Junos OS, routing protocols, and network connectivity. Use the CLI to display more information about alarms. 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.