Description of the problem

HARD_BAD is reported on a 3500 board at a location in country X. The master reports this alarm, so its first parameter is the board number of the real detected failure. As shown in the figure, it is No. 7, slot 15 single board failure, in the network management query single board information, the slot no single board.

Processing

For the master control, implement soft reset and hard reset on the network management for the master control, the alarm is not eliminated.

Perform soft reset and hard reset operations on the AUX single board, the alarm is not eliminated.

Do full DC acquisition on network elements and analyze.

Analyze the data and find that through cfg-get-phybd, there is a WDM MR4 single board inserted in this slot. Therefore, it is believed that the WDM single board causes the master to report, and after pulling out the MR4 single board, the alarm disappears.

Root cause

Analyzing the reporting mechanism of detecting HARD_BAD, the alarm is to detect the 8K and 2K in-bit lines to judge. For MR4 WDM single board, because it does not have 8K2K in place line, if the host checks the 8k2k in place line of MR4 at this time, it must be abnormal, so the host software, when judging the inserted single board is MR4 WDM single board, it directly thinks that the 8k2K in place line is normal, and it does not report the alarm.

If only insert MR4 single board, without adding the logic board, due to the MR4 single board and the main control of no board-to-board communication, the board type can not be reported to the host, the host software does not know that the inserted single board is MR4, the host will still check the 8k2k in place line, there will be anomalies in the report alarms. After adding the logic board MR4, the host knows that it is MR4 board, so it will not check the 8k2k in-position line, and will not report an alarm.

Solution

When mixing and inserting wave classification veneers such as MR4, be sure to add the logical veneer correctly.

The related technical information in this chapter and the troubleshooting process of SDH equipment are collected and organized by Shenzhen Optical Transmission Network Technology Company Limited (www.opticaltrans.com), please retain! Our company specializes in the sale of Huawei SDH optical transmission equipment,SDH transmission equipment.