Dear friend!
Backward defect indication. This alarm is generated when a signal failure is detected and the BDI byte value is 1. The OSC signals carried by the optical port will fail.
Procedure
1. Query whether an alarm with a higher severity is generated on the board on the U2000. If it is, handle the alarm with a higher severity.
2. If the alarm persists, check whether the corresponding board at the downstream site receives the R_LOS or R_LOF alarm on the U2000. If it does, handle the corresponding alarm at the downstream site.
Thank you!