Cisco XR 12404 - Manual (Page 100)

Chapter 4 Troubleshooting the Installation
Identifying Startup Problems
4-2
Cisco XR 12404 Router Installation Guide
OL-13830-02
Identifying Startup Problems
Startup problems are commonly due to power source failures 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
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. The MBus
module receives +5 VDC directly from the power supplies through the
backplane. When the power supply is powered 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.
• The consolidated switch fabric (CSF) containing the system clock,
immediately powers up.
• The MBus module on the RP monitors the progress of the clock and scheduler
card power on. When the CSF has powered up, the MBus module on the RP
turns on its DC-DC converter powering up the RP.
• The RP sends instructions to each line card to power up. Each line card
processor begins to perform its own boot process and notifies the RP when
the boot process is complete through its MBus module.
• As the boot process progresses for each card, the status of the card is shown
on the alphanumeric LED displays. The left display is powered by the DC-DC
converter on the card; the right display is powered by the DC voltage that
powers the MBus module.
By checking the state of the LEDs on the power supplies and the alphanumeric
displays on the RP and line cards, you can determine when and where the system
failed in the startup sequence.
todd.book Page 2 Monday, March 16, 2009 2:47 PM