Description

The article explains when CB failure due to power circuit being failed and steps to resolve the issue . 
 

Symptoms

Customer reported that on their box CB was not online with below alarms seen being reported. 

show chassis alarms 

3 alarms currently active

Alarm time        Class Description

2024-03-13 02:31:36 UTC Minor Loss of communication with Backup RE

2024-03-13 02:31:17 UTC Minor CB 1 Fabric Chip 1 Not Online

2024-03-13 02:31:16 UTC Minor CB 1 Fabric Chip 0 Not Online

Run the show chassis environment CB command to check CB status . 

CB 1 status
State Online <--CB1 status shows online . However, Power 1 and Power 2 lane being disabled . 
Power 1 Disabled
Power 2 Disabled

Solution

Power circuits on SBC controls the MPC cards. Failure of both powers circuit means the control board will be unable to provide power to the MPC cards. Perform below steps to resolve the issue . 

1. Offline and Online of problematic CB from primary routing engine to see if it helps to resolve the issue . Halt the routing engine first and then perform Offline and Online of CB .

2. If above steps doesn't resolve the issue then physical reseat can be tried of the CB to see if the issue gets cleared with it . 

3. Swap a working with CB with the faulty CB to see if RE comes back online or not to rule out issue with RE .  

4. If above above steps determines CB is faulty then proceed for RMA for CB. 

Modification History

2024-04-02 : Article Created