1-64
Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
78-17742-02
Chapter 1 General Troubleshooting
1.12.1 Fiber Cut Detection
Figure 1-24 LOS Indication on the OLA Node OPT-BST
Note An EOC condition is always present on both nodes, because the optical service channel (OSC) link (to
which the communication channel applies) is down.
Note For the OSCM card, only an LOS (OC-3) alarm is present at the SONET layer (Port 1).
1.12.1.2 Scenario B
Scenario B has the following conditions:
• ALS Mode = DISABLE on OPT-BST (+ OSCM) and OSC-CSM
• Fiber cut on the fiber between the OLA-TX node and the ROADM-RX node
Because the ALS protocol is disabled, the signal is lost on only the affected fiber (power is not shut down
on both fibers).
The LOS (OTS or AOTS) alarm is raised by the ROADM-RX node that was receiving the signal coming
from the broken fiber. The final fault condition of the network is shown in Figure 1-25.