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Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
78-17742-02
Chapter 1 General Troubleshooting
1.12.2 System Restart after a Fiber Cut
In node view (single-shelf mode) or shelf view (multishelf mode), the alarm panels of the two nodes
(ROADM and OLA in this example) show the LOS (OTS or AOTS) condition on the LINE-RX port of
the OPT-BST or OSC-CSM.
An EOC condition is always present on both nodes because the OSC optical link is down due to an
incoming power level lower than the optical sensitivity limit (–42 dBm). The system condition remains
unchanged as illustrated in Figure 1-22.
Every 100 seconds, the ALS protocol turns up the OSC TX laser in a pulse mode (pulse duration =
2 seconds), but the excessive loss on the span prevents the OSC link from synchronizing, and the MSTP
system remains unoperational.
Note During the attempt to restart, a valid power value is reported by the OSC transmit card (in the example,
the OSC-CSM in the OLA node), but on the OSC receive card (the OSCM in the ROADM node), the
alarm condition persists.
Corrective Action for Scenario 1
Step 1 Follow these steps to verify the alarms for both DWDM nodes that are connected to the repaired span:
a. Double-click the card directly connected to the span (either the OPT-BST or the OSC-CSM).
b. Click the Alarms tab.
c. Verify that a LOS condition is present on the LINE-RX port.
d. Click the Synchronize button on the bottom left of the window.
e. If the alarm is correctly reported, move to Step 2. If not, close the CTC application and delete the
CTC cache. Then reopen the CTC connection, and repeat Step 1.
Note If the gray color persists on the span, log into the Technical Support Website at
http://www.cisco.com/techsupport for more information or call Cisco TAC (1-800-553-2447) in
order to report a service-affecting problem.
Step 2 Isolate the fiber affected by the excessive insertion loss. For the two fibers belonging to the span, identify
the one for the W–E line direction.
a. Go into the upstream node and identify the OSCM or OSC-CSM card that manages the OSC
termination for the faulty span.
b. Double-click the card, then click the Maintenance tab.
c. Force the OSC-TX laser active by setting ALS Mode to DISABLE.
d. Go into the downstream node and verify the OSC Power level received.
• If a pair of OPT-BST + OSCM cards terminate the OSC connection, click the Provisioning >
Optical Line > Parameters tabs, then verify that there is power for OSC-TX (Port 4).
• If an OSC-CSM terminates the OSC connection, click the Provisioning > Optical Line >
Parameters tabs, then verify that there is power for OSC-RX (Port 6).
• If no power is detected and the LOS (OC-3) alarm persists, the faulty fiber has been identified,
so go to Step 3.
e. If a power value greater than –42 dBm is detected, the fiber under test has been properly repaired.
However, it is recommended that you check the new fiber Insertion Loss value.
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