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Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
78-17742-02
Chapter 1 General Troubleshooting
1.11 Power Up Problems for Node and Cards
1.11 Power Up Problems for Node and Cards
This section explains power up problems in a node or cards typically caused an improper power supply.
Symptom You are unable to power up a node or the cards in a node.
Possible Cause Improper power supply.
Recommended Action Refer to the power information in the “Hardware Specifications” appendix of
the Cisco ONS 15454 DWDM Reference Manual.
1.12 Network Level (Internode) Problems
The following network-level troubleshooting is discussed in this section:
• Fiber cut detection
• System restart after a fiber cut
• OCHNC circuit creation failure
1.12.1 Fiber Cut Detection
A fiber cut is one of the most disruptive faults for a DWDM system because more than one channel is
potentially affected. Fault isolation must, therefore, be quick and effective.
In the Multi-Service Transport Platform (MSTP), a dedicated alarm is unambiguously associated with
the detection of a fiber cut. The alarm is LOS (OTS or AOTS) and can be raised only by the two cards
(OPT-BST and OSC-CSM) that directly interface to the span fiber. The LOS (OTS or AOTS) alarm is
associated with the physical LINE-RX port of the OPT-BST and OSC-CSM cards (in CTC, identified by
Port 5 on the OPT-BST and Port 4 on the OSC-CSM). LOS (OTS or AOTS) is the combination of the
two alarms LOS-P (OTS or AOTS) (applies to channel payload) and LOS-O (applies to the OC-3
overhead OSC signal).
The simultaneous failure of both the active channel (C band) and the service channel (1510 nm) coming
into the node is evidence of a fiber span issue, whereas either the LOS-P (OTS or AOTS) alarm alone or
the LOS-O alarm alone can only be derived from different root causes.
Note When a fiber cut occurs, the actual conditions on the affected span (for example, alarms raised on both
line directions) are strictly dependent on the network automatic laser shutdown (ALS) setting. The
network ALS setting is a function of the ALS mode configured on the appropriate cards in the system
(OPT-BST, OPT-BST-E, OPT-BST-L, OPT-AMP-L, OSC-CSM, and OSCM).
Different symptoms and scenarios can occur, depending on the network ALS settings. Consider the
linear network (four nodes) in Figure 1-21 as a reference. The scenarios are presented after the figure.
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