AC is the WDM OTM site, and B is the relay site. When the optical fiber in the transmission direction from A to B is interrupted, the WDM side of the OTU relay board at B will report an RLOS…

AC is the WDM OTM site, and B is the relay site. When the optical fiber in the transmission direction from A to B is interrupted, the WDM side of the OTU relay board at B will report an RLOS emergency alarm and run and process the OTU2_BDI on the upstream side of A. Minor alert. At the same time, the alarm continues to be transmitted to the downstream site of station B. After the alarm is processed at site C, the WDM side of the OTU board at site C will report the ODU2_PM_AILS minor alarm, and return the ODU2_PM_BDI minor alarm to the upstream WDM side of station A