Description of the problem

A line board of an OSN3500 device is found to report R_LOS and R_LOF alarms at the same time, but the alarms do not start at the same time.

The customer feels abnormal and needs to locate the cause.

:alm-get-curdata:4,0

NUM BID EID SEVERITY STATE START-TIME END-TIME PARA1 PARA2 PARA3 PARA4 PARA5

335538685 4 R_LOF CR start 2012-10-22 20:32:07 None 0x02 0x00 0x01 0xff 0xff

335538686 4 R_LOF CR start 2012-10-22 20:32:07 None 0x01 0x00 0x01 0xff 0xff

335539737 4 R_LOS CR start 2012-10-23 05:19:45 None 0x01 0x00 0x01 0xff 0xff

Processing

First, use the command :alm-set-bsrep:4,enable to turn on the alarm display switch reported by the board to the host, and find that the following data is frequently reported on the Navigotor:

#9-1019:szhw [1019-Ilam ][][2012-10-23 06:32:45+00:00]>

EVENT_ALM_BS_REPORT_N ---1019

BID EID STATE PARA1 PARA2 PARA3 PARA4 PARA5 RESV TIME

4 R_LOF end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:45

4 R_LOF start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:46

4 R_LOS end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:47

4 R_LOS start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:48

4 R_LOF end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:48

4 R_LOS end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:50

#9-1019:szhw [1019-Ilam ][][2012-10-23 06:32:50+00:00]>

EVENT_ALM_BS_REPORT_N ---1019

BID EID STATE PARA1 PARA2 PARA3 PARA4 PARA5 RESV TIME

4 R_LOF start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:50

4 R_LOS start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:51

4 R_LOS end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:52

4 R_LOS start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:53

4 R_LOF end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:53

#9-1019:szhw [1019-Ilam ][][2012-10-23 06:32:54+00:00]>

EVENT_ALM_BS_REPORT_N ---1019

BID EID STATE PARA1 PARA2 PARA3 PARA4 PARA5 RESV TIME

4 R_LOS end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:55

4 R_LOF start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:55

4 R_LOS start 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:55

4 R_LOS end 0x01 0x00 0x01 0xff 0xff 0xff 2012-10-23 06:32:57

The above data shows that R_LOS and R_LOF frequently end as well as begin, alternately reporting. And because our alarms are filtered with a dithering mechanism, when such jittery alarms exist, the dithering mechanism displays them as persistent alarms, so that two alarms, R_LOS and R_LOF, are observed on the host at the same time. After loopback localization, it was found that a fiber failure caused R_LOS and R_LOF.

Root Cause

The root cause of this problem is that the circuit board has received frequent alternating R_LOS and R_LOF alarms, and the host computer displays both alarms under the alarm dithering mechanism.

Solution

Emergency recovery measure: Repair the optical fiber. Complete solution measure: Repair the optical fiber.

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