Description of the problem

Sites A and B are 125 kilometers apart, using Huawei OSN3500 equipment N3SL16 single boards and transmitting through BA optical amplification, and when checking the performance, it is found that there are a few regeneration and multiplexing segment errors on the N3SL16 single boards docked at sites A and B. The N3SL16 single boards at sites A and B have a small number of regeneration and multiplexing segment errors.

Alarm Information

Huawei OSN3500 equipment has regeneration segment and multiplexing segment errors.

Processing

1. Measuring the optical power at the scene, the optical power is found to be -18dBm, which meets the requirements and excludes the optical power from being too low, resulting in BERs.

2, query information, OSN3500 N3SL16 V-16.2Je optical module support transmission 140 kilometers, while the scene 125 kilometers, the distance meets the requirements.

3, the scene will be SSN3SL16 plus optical attenuation after the use of pigtail self-loop, found that the BER disappeared, put through the BER reappeared.

4, replace the BA optical amplifier single board, the problem can not be solved, exclude the optical amplifier single board problem.

5, re-replace a SSN3SL16 single board, found that the error code disappeared, compared before and after the two SSN3SL16 single board, found that: the appearance of the error code of the single board FPGA version of 130, and no error code of the single board FPGA version of 200.

6, after the R & D to confirm: the problem is due to the SSN3SL16 single-board optical module scrambling signal design reasons lead to long-distance transmission may produce a small amount of error code, affecting the transmission performance.

7, SSN3SL16 200 version of the FPGA has solved the problem, the scene will SSN3SL16 V-16.2Je FPGA upgrade to version 200, while the single board software upgrade supporting the disappearance of BER.

Root Cause

1, the line attenuation is too large, the optical power is too low, resulting in BER.

2、Transmission distance is too large, beyond the transmission distance of the single board, performance degradation leads to BER.

3、Huawei SSN1BA2 optical amplifier failure leads to BER.

4、Huawei SSN3SL16 single board failure leads to error code.

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