Monitoring the Control Board
You monitor and maintain the Control Boards that provide control and monitoring
functions for the router. These functions include determining Routing Engine
mastership, controlling power, performing reset and SONET clocking for the other
router components, monitoring and controlling fan speed, and monitoring system
status using I2C controllers. (See Table 71.)
For information on monitoring the Control Boards, see “Monitoring the Host
Subsystem” on page 289.
Table 71: Checklist for Monitoring the Control Board
Monitor the Control Board Tasks
Command or Action
Understanding the Control Board on page 303
M320 Router Control Board on page 303
T320 Router Control Board on page 304
T640 Routing Node Control Board on page 304
M320 Router, T320 Router, and T640 Routing Node Control Board Location on page 305
Monitoring the Control Board Status on page 306
1. Check the Control Board Environmental Status on page 306 show chassis environment cb
2. Check the Control Board Status from the Craft Interface on
show chassis craft-interface
Check the LEDs on the Control Board faceplate.
Check the Host Subsystem LEDs on the T320 router and the
T640 routing node craft interface.
Checking the Control Board Alarms on page 308
1. Display Control Board Alarms on page 308
show chassis alarms
For conditions that trigger M320 router alarms, see Table 25
on page 74.
For conditions that trigger T320 router alarms, see Table 26 on
For conditions that trigger T640 routing node alarms, see
Table 27 on page 80.
2. Check the Control Board LEDs on page 309
Look at the LEDs on the Control Board faceplate.
3. Display Control Board Error Messages in the System Log
File on page 309
show log messages | match cb
4. Display Control Board Error Messages in the Chassis
Daemon Log File on page 309
show log chassisd | match cb
JUNOS Internet Software Network Operations Guide: Hardware
Verifying Control Board Failure on page 310
1. Check the Control Board Connection on page 310
1. Make sure th