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Analysis of the Alarms Caused by the R_LOS Alarm of the SC1 Board on the OptiX OSN 6800

Publication Date:  2012-07-25 Views:  57 Downloads:  0
Issue Description

The version of the OptiX OSN 6800 is 5.51.04.13.

The network comprises two OTM stations that are configured with bi-directional services.

The relevant boards are NS2, FIU, SC1 in station A and those in station B.

The following alarms are reported:

The SC1 in station A reports the OSC-RDI alarm.

In station B, the NS2 reports the OCH_SSF-O alarm, the FIU reports the OTS_LOS-O alarm, and the SC1 reports the R-LOS alarm.
Alarm Information
OCH_SSF-O, OTS_LOS-O, R-LOS, OSC-RDI
Handling Process

1.         It is easily confirmed that the key alarm is the R-LOS alarm reported by the SC1 in station B. The OCH_SSF-O alarm reported by the NS2 in station B and the OSC-RDI alarm reported by the SC1 in station A are caused by the R-LOS alarm.

2.         The FIU board in station B detects the OTS_LOS-O alarm. The cause for the R-LOS alarm reported by the SC1 board in station B is mistaken for the OTS_LOS-O alarm detected by the FIU. The following conclusion then is drawn: Station A is faulty, or at least the fiber connection from the FIU board to the SC1 in station B is correct. Actually, the relationship between the two alarms is misunderstood. The correct relationship is as follows: The FIU reports the OTS_LOS-O alarm because the SC1 reports the R-LOS alarm.

3.         The OTS_LOS-O alarm indicates loss of the monitoring signal (overhead) in the OTS layer. The optical port of the OSC board connecting to the TM port of the FIU board reports the OTS_LOS-O alarm because the R-LOS alarm is detected.

4.         It is confirmed that the physical fiber connection from the FIU to the SC1 in station B is incorrect. All the alarms are cleared after the fiber connection is corrected.

Root Cause

1.         The boards are faulty.

2.         The fiber connections are incorrect.

Suggestions

1.         The service alarm indicator (SRV) gives green light when the NS2 reports the OCH_SSF-O alarm or when the FIU board reports the OTS_LOS-O alarm. This means that the alarm is not generated at the board side.

2.         The two alarms are related to the logical fiber connection from the FIU to the SC1. Neither alarm is reported if no logical fiber is created from the FIU to the SC1.

3.         To handle the unfamiliar alarms, refer to the Alarms and Performance Events in the relevant product manual.

END