Service Provisioning Fails on an LHP Network, The OTU2_LOF Alarm Is Reported

The service provisioning fails on an LHP network cause by the connectors on the RPC are burnt, the OTU2_LOF alarm is reported.

Product

OptiX BWS 1600G, OptiX OSN 6800, OptiX OSN 8800

Fault Type

OTU2_LOF

Symptom

During commissioning of a long hop (LHP) network, the OTU2_LOF alarm is reported and service provisioning fails. 

Cause Analysis

To locate this type of fault, check the optical power of signals. Most exceptions are relevant to the optical power. Before locating this type of fault, make correct power budget for each section. Therefore, the fault can be avoided.

The possible causes of the fault are as follows:

• The E2000 fiber jumpers are burnt.
• Connectors on boards such as the ROP and RPC are burnt, or the laser is not enabled or fails.
• The DCM or FOA is mis-placed on the line.

Procedure

1. When the fault occurs, check whether the transmit optical power and receive optical power are normal.
2. If the receive optical power of the OA at the transmit end is abnormal, check whether the gain of the backward RPC and the gain of the ROP are normal. If the gain of the backward RPC is higher than 10 dB, it indicates that the backward RPC is normal; if the total gain of both the backward RPC and ROP is higher than 30 dB, it indicates that the backward RPC and ROP are normal. Otherwise, further check whether the E2000 fiber jumpers or connectors on the RPC are normal.
3. Use a microscope to check the connectors of the fiber jumpers on the E2000. If the connectors are dirty, clean the connectors. If the connectors are burnt, replace the fiber jumpers.
4. Check whether the gain of the laser on the RPC is abnormal. Check whether the pump laser on the RPC is enabled. If the laser is not enabled, enable it and then check the gain of it.
5. If the gain is still abnormal at this time, check whether the pump optical power equals the pre-set value. If the pump optical power is lower than the pre-set value, use a microscope to check the connectors on the RPC. If the connectors are normal, it indicates that the laser fails.
6. Based on the preceding analysis, it is determined that the root cause of the fault is that the connectors on the RPC are burnt. Due to burnt connectors, the Raman gain of the RPC is insufficient and service provisioning fails.

Result

The problem is resolved.

Reference Information

None.

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