RPR Network Interruption Due to Incorrect Fiber Connections

Incorrect fiber connections may result in RPR network interruption. In this case, connect the fibers correctly and re-configure the cross-connections.

Product

• OptiX OSN 1500A/1500B
• OptiX OSN 2500
• OptiX OSN 3500 II
• OptiX OSN 3500
• OptiX OSN 7500

Fault Type

• RPR
• Ethernet fault

Symptom

The fibers are incorrectly connected. In this case, the RPR_NB_INCONSIS alarm is reported, which results in the RPR network interruption. Figure 1 shows incorrect fiber connections.

Figure 1 Incorrect fiber connections

Cause Analysis

The previous fault is caused due to incorrect fiber connections. In this case, ringlet0 receives packets from ringlet1 or ringlet1 receives packets from ringlet0.

As shown in Figure 1, the eastbound adjacent node of S2 is S3 but the westbound adjacent node of S3 is S1 rather than S2. Thus, the RPR_NB_INCONSIS alarm is reported.

Procedure

1. Query the cross-connection configuration on each board to check whether there are cross-connections that are not completely configured on a board. Configure cross-connections from the Ethernet board to the SDH line board for each NE. See Reference Information.
2. Check whether the fiber connections on the line board are correct. Connect fibers to make the input and output interfaces of the optical modules match. Figure 2 shows links between nodes. After fibers are connected properly, the alarm is cleared and the fault is rectified.
   Figure 2 Correct fiber connections
   

Reference Information

The steps of configuring Cross-Connections:

1. In the Main View, select the desired NE. Right-click the NE and choose NE Explorer from the shortcut menu.
2. Choose Configuration > SDH Service Configuration from the Function Tree.
3. Click Create in the lower right of the window. The Create SDH Service dialog box is then displayed.
4. Set the parameters in the dialog box as follows:
   • Level: VC-4
   • Direction: Bidirectional
   • Source Slot: 13-N2EGR2-1
   • Click . In the Please select the source timeslot dialog box, set the following parameters.
     • Port: 1
     • Higher Order Timeslot: 1,3,5,7,9,11,13,15
   • Sink Slot: 12-N2SL16-1(SDH-1)
   • Sink Timeslot Range: 1-8
   • Activate Immediately: Yes
   • Then, click Apply.
5. Based on the operations in Step 4, set the parameters in the dialog box as follows:
   • Level: VC-4
   • Direction: Bidirectional
   • Source Slot: 13-N2EGR2-1
   • Click . In the Please select the source timeslot dialog box, set the following parameters.
     • Port: 1
     • Higher Order Timeslot: 2,4,6,8,10,12,14,16
   • Sink Slot: 7-N2SL16-1(SDH-1)
   • Sink Timeslot Range: 1-8
   • Activate Immediately: Yes
   • Then, click Apply.