This article discusses about mastership switchover on MX router with SCBE3 card when error hits on the SyncE (Synchronous Ethernet) configured interfaces.

When the error is injected on the SyncE configured interface, the Master RE/CB will switchover.

The below logs will be seen when this issue is hit.

<date> <time> <hostname> alarmd[40205]: Alarm set: CB id=436207734, color=RED, class=CHASSIS, reason=CB 0 19.44 MHz clock failure
<date> <time> <hostname>   craftd[17160]:  Major alarm set, CB 0 19.44 MHz clock failure

On Junos MX240/MX480/MX960 platforms with SCBE3 and with the injection of error on the SyncE (Synchronous Ethernet) configured interfaces, RE (Routing Engine)/CB (Control Board) switchover will be observed.

If the customer is conducting some SyncE related test, suggest them to stop injecting the errors.

In this case, the customer was injecting a test clock failure by sending frequency offset of 10ppm which makes the clock source unusable. This lead to the CB clock failure alarm and eventually the RE switchover.

This issue might be seen if the following conditions are met:
* On Junos MX240/MX480/MX960 platforms with SCBE3 
* When the error is injected on the SyncE configured interface