Description of the problem

As shown in the figure below, two OSN9500 and five OSN3500 network elements form an MSP ring. When the fiber is disconnected between the network elements Telecom-548 and Telecom-590, the multiplexing segment inversion fails, and service interruption occurs.

Processing

OSN9500 network element host software version: 5.15.04.19P01 _ OSN3500 network element host software version: 5.21.18.50

550 network element error code K bytes:

5 486 K_RECEIVED 0xfff8 2011-2-15 12:52:38 0x01f893bd

5 487 K_DIR 0x0002 2011-2-15 12:52:38 0x01f893c3

570 Network element error code K bytes:

5 1770 K_RECEIVED 0xfff8 2011-2-15 12:55:46 0x00c7a318

5 1771 K_DIR 0x0002 2011-2-15 12:55:46 0x00c7a31e

548 Network element error code K bytes:

1 64728 K_RECEIVED 0xfff8 2011-02-15 20:54:10 0x006010bc

1 64729 K_DIR 0x0002 2011-02-15 20:54:10 0x006010c6

590 Network element error code K bytes:

1 60810 K_DIR 0x0000 2011-02-15 20:52:22 0x00ece4ab

1 60811 K_RECEIVED 0xfff8 2011-02-15 20:52:22 0x00eceaec

1 60812 K_DIR 0x0000 2011-02-15 20:52:22 0x00eceaf6

1 60813 K_RECEIVED 0xffb8 2011-02-15 20:52:22 0x00f32c86

1 60814 K_DIR 0x0000 2011-02-15 20:52:22 0x00f32c91

1 60815 K_RECEIVED 0xfff8 2011-02-15 20:52:22 0x00f332cf

1 60816 K_DIR 0x0000 2011-02-15 20:52:22 0x00f332da

547 Network element error code K bytes:

1 22060 K_RECEIVED 0xfff8 2011-02-15 23:36:59 0x01ee1146

1 22061 K_DIR 0x0000 2011-02-15 23:36:59 0x01ee1152

1 22062 K_RECEIVED 0xb23a 2011-02-15 23:49:31 0x00aed327

1 22063 K_DIR 0x0000 2011-02-15 23:49:31 0x00aed332

1 22064 K_RECEIVED 0xfff8 2011-02-15 23:49:35 0x00e957f2

1 22065 k_dir 0x0000 2011-02-15 23:49:35 0x00e957fd

1 22066 K_RECEIVED 0xff38 2011-02-15 23:49:35 0x00e95c03

1 22067 k_dir 0x0000 2011-02-15 23:49:35 0x00e95c0e 3

545 Network element error code K bytes:

1 56735 K_RECEIVED 0xffb8 2011-02-15 23:36:37 0x01ca253b

1 56736 K_DIR 0x0000 2011-02-15 23:36:37 0x01ca2546

1 56737 XC_EXECUTE 0x0000 2011-02-15 23:36:37 0x01ca2809

1 56738 STATE_TRANS 0x0800 2011-02-15 23:36:37 0x01ca2d3d

1 56739 K_RECEIVED 0xfff8 2011-02-15 23:36:37 0x01ca2e5c

1 56740 K_DIR 0x0000 2011-02-15 23:36:37 0x01ca2e65

546 Network element error code K bytes:

1 25734 K_RECEIVED 0xffb8 2011-02-15 20:51:22 0x03c4d443

1 25735 K_DIR 0x0000 2011-02-15 20:51:22 0x03c4d44d

1 25736 K_RECEIVED 0xfff8 2011-02-15 20:51:22 0x03c4d9a0

1 25737 K_DIR 0x0000 2011-02-15 20:51:22 0x03c4d9aa

According to the full ring K byte analysis, 550, 570 and 548 network elements have received 0xfff8 error K bytes in the east direction, and 546, 545, 547 and 590 have received 0xfff8/0xffb8 error K bytes in the west direction, as shown in the figure below:

From the analysis of the distribution of the error code and the starting point of the error code generation, the failure point is the eastward line veneer board 23 of the 550 network element and the westward line veneer board 8 of the 546 network element, and also the K byte related to the overhead clock generated by the 550 network element and the 546 network element is also a possible point of failure.

Through the field to replace the single board and the main backup reversed single board operation for one by one investigation:

1, after replacing the 546 network element 8 line board, the fault does not disappear, and still receive the error code K bytes.

2. After replacing line board No. 23 of the 550 network element, the fault does not disappear and the error code K bytes are still received.

3、After inverting and replacing the STG single board of OSN9500 network element 550, the fault disappeared and the K bytes returned to normal.

This proves that there is a problem with the overhead clock generated by the 550 network element at the point of failure.

Root cause

Clock board failure on 9500 network element #550-9, MSP reversal back to normal after primary and backup reversed clock boards.

Solution

Emergency recovery measures:

Primary and backup reverse clock boards.

Complete resolution measures:

Replace the faulty clock board.

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