Signal degraded before FEC. Signals sent from the WDM side of the opposite-end OTU have the FEC function. As a result, before performing signal FEC in the receive direction on the WDM side of the local-end OTU, the local-end OTU counts the bit error rate. This alarm is generated when the counted bit error rate crosses the threshold.
Alarm Severity
Alarm Type
Minor
Service alarm
None
The error tolerance of the system decreases, which may even affect the quality of signals.
Fault Symptom
Table 1 lists the fault symptom of the BEFFEC_EXC alarm.
Table 1 Fault symptom for the BEFFEC_EXC alarm
Fault Symptom
Cause
The NE that reports this alarm reports a temperature alarm or fan fault alarm, such as TEMP_OVER or FAN_FAIL, within a certain time.
Cause 3 of this alarm in the case of multiple wavelengths: The external environment is improper.
NOTE:
If the fault has no symptom, or if the fault symptom is not covered in this topic, handle the fault according to "Procedure" provided in this topic.
The possible causes of this alarm in the case of a single wavelength are as follows:
· Cause 1: The input optical power of the OTU board is excessively high or low.
· Cause 2: The settings of the FEC mode of the interconnected OTU boards are different.
· Cause 3: The fiber between the OTU board and the multiplexer/demultiplexer board is faulty.
· Cause 4: An inappropriate DCM is installed.
· Cause 5: The board that reports this alarm or the board at the opposite station is faulty.
The possible causes of this alarm in the case of multiple wavelengths are as follows:
· Cause 1: Fibers in the optical cables between stations or the multiplexing portions inside a station are faulty.
· Cause 2: The attenuation of the signals during line transmission is excessively high.
· Cause 3: The external environment is improper.
1. On the U2000, check the alarm information and record the IDs of the port and channel where the alarm is generated.
2. Cause 1 of this alarm in the case of a single wavelength: The input optical power of the OTU board is excessively high or low.
a. Check whether the receive optical power on the U2000 is within the permitted range. For the optical power specifications of the specific board, see "Technical Specifications" in the Product Description.
NOTE:
See "Querying Optical Module Information" in the Supporting Tasks or "Bar Code for Boards" in the Hardware Description to obtain the manufacturer information of the optical module on the board.
b. If the input optical power is abnormal, see the methods for handling the IN_PWR_HIGH and IN_PWR_LOW alarms.
c. If the input optical power is normal but the alarm persists, see the alarm handling procedure for cause 2 of this alarm in the case of a single wavelength.
3. Cause 2 of this alarm in the case of a single wavelength: The settings of the FEC mode of the interconnected OTU boards are different.
a. On the U2000, check the settings of FEC mode of the two interconnected OTU boards. If the settings are different, change the settings to FEC or AFEC to ensure consistency. For details, see "Setting the FEC Mode" in the Supporting Tasks.
b. Check whether the alarm is cleared. If the alarm persists, see the alarm handling procedure for cause 3 of this alarm in the case of a single wavelength.
4. Cause 3 of this alarm in the case of a single wavelength: The fiber between the OTU board and the multiplexer/demultiplexer board is faulty.
a. Check the related fiber connectors. If the fiber connectors are dirty, clean or replace them. For details, see "Inspecting and Cleaning the Fiber-Optic Connectors" in the Supporting Tasks.
b. If the alarm persists, check the fiber jumper. If the fiber jumper endures a large bending radius or it is damaged or aging, adjust or replace the fiber jumper. For details, see "Replacing Fiber Jumpers" in the Parts Replacement.
c. Check whether the alarm is cleared. If the alarm persists, see the alarm handling procedure for cause 4 of this alarm in the case of a single wavelength.
5. Cause 4 of this alarm in the case of a single wavelength: An inappropriate DCM is installed.
a. Check whether the DCM used on the existing network is appropriate. If not, replace the DCM.
b. Check whether the alarm is cleared. If the alarm persists, see the alarm handling procedure for cause 5 of this alarm in the case of a single wavelength.
6. Cause 5 of this alarm in the case of a single wavelength: The board that reports this alarm or the board at the opposite station is faulty.
a. If the alarm is reported simultaneously on the IN port of both the OTU(A)
and OTU(B) boards, as shown in the following figure, add a pigtail to connect a
5 dB fixed attenuator and the OTU(B) board and perform a WDM-side loopback. If
the alarm persists, the OTU(B) board is faulty. If the alarm is cleared, the
OTU(B) board is normal but the OTU(A) board may be faulty.
b. Release the loopback on the OTU(B) board. Add a pigtail to connect a 5 dB fixed attenuator and the OTU(A) board on the opposite station and perform a WDM-side hardware loopback. If the alarm on the OTU(A) board persists, the OTU(A) board is faulty.
c. Replace the faulty board. Check whether the alarm is cleared.
If ...
Then ...
The board supports pluggable optical modules,
Replace the specific pluggable optical module.
The board does not support pluggable optical modules,
7. Cause 1 of this alarm in the case of multiple wavelengths: Fibers in the optical cables between stations or the multiplexing portions inside a station are faulty.
a. Check the related fiber connectors. If the fiber connectors are dirty, clean or replace them. For details, see "Inspecting and Cleaning the Fiber-Optic Connectors" in the Supporting Tasks.
b. If the alarm persists, check the fiber jumper. If the fiber jumper endures a large bending radius or it is damaged or aging, adjust or replace the fiber jumper. For details, see "Replacing Fiber Jumpers" in the Parts Replacement. If the fibers inside a station are normal, check the optical cables between stations to rectify the fault.
c. Check whether the alarm is cleared. If the alarm persists, see the alarm handling procedure for cause 2 of this alarm in the case of multiple wavelengths.
8. Cause 2 of this alarm in the case of multiple wavelengths: The attenuation of the signals during line transmission is excessively high.
a. Check the attenuation of the multiplexing portions inside a station and the line attenuation between stations section by section. If the preset attenuation values are excessively large, correct them so that they are within the permitted range.
b. Check whether the alarm is cleared. If the alarm persists, see the alarm handling procedure for cause 3 of this alarm in the case of multiple wavelengths.
9. Cause 3 of this alarm in the case of multiple wavelengths: The external environment is improper.
a. Check the ambient temperature inside the telecommunications room, the cleanliness of the air filter, and the heat dissipation conditions of each fan. For details, see the procedure for handling the TEMP_OVER alarm.
b. Check whether the alarm is cleared. If the alarm persists, check whether external electromagnetic interference exists. For example, whether there is external electronic equipment, whether the power supply is unstable, and whether the lightning electromagnetic interference exists, or whether a high-voltage output cable generates electromagnetic interference. If yes, take corresponding measures to withstand the electromagnetic interference.
c. Check whether the alarm is cleared. If the alarm persists, contact Huawei for assistance.
