Description of the problem

Two sets of OSN3500 equipment main expansion subrack 1+1 linear multiplexing segment networking, one day expansion subrack 3500 of the standby cross board 10-GXCSA reported SYN_BAD, HARD_BAD, BUS_ERR, HSC_UNAVAIL alarm, check the performance of the network elements found that there are a large number of TU pointer adjustments on the branch ports. Host version 5.21.18.50.

Alarm Information

Huawei OSN3500 device SYN_BAD HARD_BAD BUS_ERR HSC_UNAVAIL

Processing

1. Analyzing the alarms, the customer suspected that the 10-GXCSA was faulty, so after replacing the 10-GXCSA, the customer observed that SYN_BAD, HARD_BAD, BUS_ERR, and HSC_UNAVAIL alarms were still being reported;

2, further inspection of network element alarms, found that Huawei OSN3500 equipment GXCSA currently exists SYN_BAD alarm, worried about the possibility of failure of the 9-GXCSA, so replace the 9-GXCSA single board, and the 9-GXCSA re-inverted for the main cross-clock board, to observe the failure phenomenon remains;

3, so suspected of receiving line or upstream clock source quality deterioration, change the network element line clock source, observe the failure remains;

4, the main backup inverted upstream main sub-frame cross-clock board, then SYN_BAD, HARD_BAD, BUS_ERR, HSC_UNAVAIL alarm disappeared, replace the main sub-frame 9-slot cross-clock board, and inverted for the main, the alarm is not re-reported, localized for the upstream network elements of the main cross-clock board failure.

Root cause

1. Cross-clock board failure at this station;

2. Failure of the optical board at this station or the upstream station, resulting in deterioration of the quality of the line clock source;

3, upstream station cross-clock board failure, resulting in this station receiving clock quality deterioration.

Suggestions and Summary

Although the Huawei OSN3500 device SYN_BAD alarm is a minor alarm, it may lead to BUS_ERR, HSC_UNAVAIL, and the standby cross-board clock is phase-locked to the main clock board clock, so the standby clock board deteriorates with the deterioration of the clock source of the main clock board; therefore, it is necessary to check the main and standby clock board alarms during similar troubleshooting, so as to avoid incomplete alarm information. Therefore, it is necessary to check the alarms of the main and standby clock boards during similar troubleshooting to avoid incomplete alarm information, which affects the processing efficiency.