SNCP Protection Switching Fails Due to Incorrect Fiber Connections

The SNCP protection switching fails due to incorrect fiber connections.

Product

OptiX OSN 6800

OptiX OSN 8800

WDM

Fault Type

Protection

Symptom

In one provincial backbone ring network, the network consists of multiple sites and is configured with the SNCP protection. However, the SNCP protection switching fails during commissioning of the network.

Figure 1 The Network Topology of One Provincial Backbone Ring Network

Cause Analysis

The possible causes of the fault are as follows:

• The parameters of the SNCP protection group are set incorrectly.
• The board on the protection path is faulty.
• The fiber connections are established incorrectly.

Procedure

1. Confirm that the SNCP protection group is configured correctly.
2. Confirm that the boards on the working and protection paths work normally and have not reported any fault-related alarm.
3. Check the network configurations against the fiber connection diagrams in engineering design documents and find that fiber connections are established incorrectly at an OTM site. After correcting the fiber connections, perform SNCP protection switching again and find that protection switching is successful.
   The following figure shows the fiber connection diagram for site OTM.
   
   The following figure shows how the fibers at site OTM are connected.
   

Result

The problem is resolved.

Reference Information

Conclusions and suggestions for this case are as follows:

Check the fiber and cable connections in each deployment phase of the network to ensure that boards, subracks, and network cables are connected correctly.

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