4-15
Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
OL-11497-03
Chapter 4 Troubleshooting the Installation
Problem Solving with Subsystems
• Cooling subsystem—Consists of the blower module, which circulates air
through the card cages to cool the cards, and the fan in each of the power
modules, which circulates cooling air through the power module bays.
• Processor subsystem—Includes the RP, up to five line cards (when no
optional, redundant RP is installed), and two alarm cards, which are located
in the alarm card cage directly below the CSC card cage. The RP and the line
cards are equipped with onboard processors. 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.
The system uses two four-character alphanumeric LED displays (at one end
of the faceplate on each line card and RP) to display status and error
messages, which can help in troubleshooting.
Identifying Startup Problems
Startup problems are commonly caused by the power source or by a card that is
not seated properly in the backplane. Although an overtemperature condition is
unlikely at initial startup, the environmental monitoring functions are included
here because they also monitor internal voltages.
When you start up the router for the first time, you should observe the startup
sequence. The normal startup sequence is as follows:
• Each card in the system has an MBus module and at least one DC-DC
converter. Each MBus module controls the DC-DC converter for its card. The
MBus module receives direct current voltage 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. These pins tell the MBus module processor what kind of card it is
mounted on, which determines how the MBus module will function.
• The clock and scheduler card (CSC), containing the system clock,
immediately powers up.
• The MBus module on the RP monitors the progress of the CSC power up.
When the CSC has powered up, the MBus module on the RP turns on its
DC-DC converter, powering up the RP.