Hello, everyone!
Today, I'd like to share a case with you.
Product Model: OSN 902
Problem Description
A customer(GMT+3) reported that the alarm reporting function of the M201 board on an OSN 902 was abnormal.
When the customer switches off the supports of the 6-C5 port on the M201 board one by one from client-side equipment, not all ports on the M201 board display loss alarm.
1. When the customer switches off LANE1 and LANE2 of the 6-C5 port on the SKV site one by one from client-side equipment, LANE1 and LANE2 are reported LANE_LOS.
2. When the LANE1 of the 6-C5 port on V19 site was interrupted and the LANE_LOS alarm was reported, then the customer switched off LANE2 of the 6-C5 port and no LANE_LOS alarm was reported, but C5 port reported R_LOS alarm.
U2000 version: V200R018C60SPC501
OSN902 version: V100R003C00SPC200
Problem Analysis
1. Through communication, I knew that the type of optical module and optical cable used by customer is MPO.
2. Data Collection
a) SKV site
Alarm Log:
Interface Use Status:
Slot | Client Port | Lane | Channel Use Status |
6 | C5 | Lane1 | Used |
Lane2 | Used | ||
Lane3 | Used | ||
Lane4 | Used |
b) V19 site
Alarm Log:
Interface Use Status:
Slot | Client Port | Lane | Channel Use Status |
6 | C5 | Lane1 | Used |
Lane2 | Used | ||
Lane3 | Unused | ||
Lane4 | Unused |
3. Data Analysis
a) At 19:35 on June 11th, the customer shut down the client-side lasers on lanes 1 and 2 of slot 6 at site SKV, then lane1 and lane2 reported LANE_LOS alarms.
b) At the V19 site, only the R_LOS alarm was reported, and no LANE_LOS alarm was reported.
c) Observe the following alarms (marked red in the preceding figure) and interface use status. The R_LOS and LANE_LOS alarms are not reported at the same time. The end time of the LANE_LOS alarm on lane1 is the start time of the R_LOS alarm. When the R_LOS alarm is cleared, lane1 reports the LANE_LOS alarm. The 15-minute period indicated that the alarm reported was consistent with the performance event. Therefore, we determined that the client-side laser on channel 2 was turned on and off for multiple times.
Therefore, I think that R_LOS and LANE_LOS are suppressed. When both LANE2 and LANE3 are in the unused state, disabling LANE1 and LANE2 means that the entire C5 port does not receive optical signals. As a result, the R_LOS alarm is reported. So the alarms reported by the device are normal.
Root Cause
The root cause is alarm suppression.
1. If one of the subchannels is interrupted, the support report LANE_LOS.
2. If all of the subchannels are interrupted, then the client port report R_LOS， the LANE_LOS is suppressed.
Solution Description
The alarm rules of the board are the same. This is normal.
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