Problem Solving; Ok Led Diagnostics - Cisco 1721 - VPN Security Router Bundle Hardware Installation Manual

Chapter 3 Troubleshooting
Step 3
Step 4

Problem Solving

OK LED Diagnostics

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Press Ctrl-Z to exit configuration mode:
Router(config)# Ctrl-Z
Reboot the router, and enter the recovered enable password.
The key to problem solving is to isolate the problem to a specific subsystem by
comparing what the router is doing to what it should be doing.
In problem solving, consider the following subsystems of the router:
WICs—Refer to the LEDs on the cards and the LEDs on the router front panel
•
to help identify a failure. For more information on WICs, refer to the
Cisco WAN Interface Cards Hardware Installation Guide, which comes with
each card.
Cables—Check all the external cables that connect the router to the network.
•
• Power system—Check the external power source, power cable, router power
supply, and circuit breaker. Check for inadequate ventilation or air circulation
that might cause overheating.
ISDN configuration—Consider ISDN-specific hardware and software
•
configurations (ISDN BRI WICs only).
Use the front-panel OK LED to determine any problems with the router. When the
router first boots up, it performs a power-on self-test (POST). If the router detects
a problem during the POST, the OK LED blinks in different patterns (described
in Table 3-1), depending on the problem. A pattern consists of a specific number
of blinks that is repeated until the router is turned off. If the router experiences
any of these problems, contact your Cisco reseller.
Cisco 1721 Router Hardware Installation Guide
Problem Solving
3-7