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Troubleshooting Overview
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Processor subsystem—includes the Route Processor RP, and all line cards. Each card
has an onboard processor. The RP downloads a copy of the Cisco IOS image to each line
card processor. A line card or RP that is partially installed in the backplane might cause
the system to hang and crash. Two 4-character alphanumeric LED displays at the bottom
of each line card or RP faceplate display status and error messages, which can aid in
troubleshooting.
Identifying Startup Problems
Startup problems are commonly due to source power or to a card not properly seated in the
backplane. Although an overtemperature condition is unlikely at initial startup, the
environmental monitoring functions are included in this chapter because they also monitor
internal voltages.
When you start up the router for the first time, you should observe the startup sequence.
This section contains a description of the normal startup sequence as follows:
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Each card in the system has an MBus module and at least one DC-DC converter. Each
MBus module controls the DC-DC converter. The MBus module receives +5 VDC
directly from the power supplies through the backplane. When the power supply power
switches are turned on, each MBus module boots from an onboard electrically erasable
programmable read-only memory (EEPROM) device. Each MBus module processor
reads a set of identification pins on the card to the backplane connector telling the MBus
module processor what kind of card it is mounted on, which in turn, determines how the
MBus module will function.
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The clock and scheduler card (CSC), containing the system clock, immediately powers
up.
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The MBus module on the RP monitors the progress of the clock and scheduler card
power up. When the CSC has powered up, the MBus module on the RP turns on its
DC-DC converter powering up the RP.
5-4 Cisco 12012 Gigabit Switch Router Installation and Configuration Guide
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Table of Contents
Troubleshooting
