Description of the problem

Huawei OSN3500 devices form an SNCP ring, and the network diagram is shown below.

There is an E1 from station E to station F. Due to the special requirements of the electric power industry, the E1 does not take the short path E-F, but takes the longest path E-D-C-B-A-F, and is not equipped with SNCP protection, running on an unprotected chain. Customers have reported that the E1 breaks down at irregular intervals, and the ports of station F report the TU_AIS alarm, while the ports of station E report the LP_RDI alarm.

Alarm information

TU_AIS

LP_RDI

Processing

1. Because the service is only instantaneous, and take a long path, passing through many stations, the frequency of failure is low, sometimes once a day, sometimes did not occur, increasing the difficulty of troubleshooting.

2. query the 15-minute SDH performance monitoring of the equipment of the stations through which the E1 is passing, and found that the S11 slot of station A and the S8 slot of station B have performance overruns at irregular intervals, and queried the receiving and transmitting power of the S11 slot of station A and the S8 slot of station B, which are all in the normal range.

3. A of the clock tracking S11 slot line clock, business transient break in the abnormal event to see the A station clock switching, from the S11 slot line clock switched to the internal clock, after a period of time and cut back to the S11 slot line clock, business transient break in the A station has an SCNP abnormal event, the preliminary judgment is that there is a failure between the A station and the B station, but still can not determine that the board faults

4. Considering the relatively low frequency of this fault, the 15-minute performance monitoring data is likely to be incomplete, because the 15-minute performance monitoring only 16 registers, open the 24-hour performance monitoring to continue to observe

5. the next day to the network management to check another service transient break, 24 hours of performance data show: station B to the A station of the optical amplifier COA output power fluctuations, luminous maximum value is: 19.3 dBm, minimum value is: 9.3 dBm, with the COA standard output optical power 17 dBm difference is large, the corresponding A station of 11 slots of the board of the receiving optical power fluctuations, maximum receiving power of -14 dBm, the maximum power of -14 dBm, the maximum receiving power of -14 dBm, the maximum receiving power of -14 dBm, the maximum receiving power of -14 dBm, the maximum receiving power of -14 dBm, the maximum receiving power of -14 dBm, the maximum receiving power of -14 dBm. The maximum received power is -14dBm, and the minimum received optical power is -25.9dBm. The fault is localized to the abnormal output power of external COA, which leads to service interruption.

Root cause

Huawei OSN3500 equipment external optical amplifier COA luminous abnormality, the luminous power fluctuates greatly at irregular moments, resulting in instantaneous service interruption.

Solution

Replace Huawei external optical amplifier COA to solve the problem

Suggestions and Summary

In troubleshooting, for part of the business interruption, first of all, we should find out the commonality of the interruption of business, which is conducive to fault location, and secondly, we should collect as comprehensive information as possible, and then carry out a comprehensive analysis of the troubleshooting process, the beginning of the process, ignoring the role of 24-hour performance monitoring to monitor the stability of the operation of the equipment, which led to difficulties in localization.

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