Cisco XR 12406 - Manual (Page 160)

Chapter 4 Troubleshooting the Installation
Troubleshooting the Processor Subsystem
4-30
Cisco XR 12406 Router Installation Guide
OL-13831-01
Monitoring Critical, Major, and Minor Alarm Status
The alarm card uses three pairs of alarm status LEDs to identify system alarm
conditions detected through the MBus. Those alarm conditions are:
• Critical
• Major
• Minor
Note The alarm status LEDs are paired for redundancy to protect against a
single failed LED. If any of the six LEDs is on, check the system console
for messages describing the fault.
Because there are two alarm cards in the Cisco XR 12406 router, a system
alarm condition detected through the MBus causes the same LEDs to light
on both alarm cards.
The alarms can warn of an overtemperature condition on a component in one of
the card cages, a fan failure in a blower module, an overcurrent condition in a
power supply, or an out-of-tolerance voltage on one of the cards in one of the card
cages. The LEDs are driven by MBus software, which sets the threshold levels for
triggering the different stages of alarms.
The RP continuously polls the system for temperature, voltage, current, and fan
speed values. If an over-threshold value is detected, the RP:
• Sets the appropriate alarm severity level on the alarm card
• Lights one of the LEDs on the alarm display
• Energizes the appropriate alarm display relays
• Activates any external audible or visual alarms wired to the alarm display
• Logs a message about the threshold violation on the system console