You can use the radiusSendAttributes system event log category to troubleshoot applications that use PPPoE remote circuit ID capture. The radiusSendAttributes event category logs RADIUS attributes added to outbound RADIUS requests.
You can also use the log severity debug pppoeControlPacket command to configure a packet trace log for a PPPoE interface that includes the PPPoE remote circuit ID value captured on that interface. For information about how to use the log severity debug pppoeControlPacket command, see Troubleshooting.
For information about how to log system events, see Overview of System Logging.