Cisco ONS 15454 Troubleshooting Manual page 46

1.1 Troubleshooting Circuit Paths with Loopbacks
The remaining sections describe symptoms, problems, and solutions that are categorized according to
the following topics:
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1.1 Troubleshooting Circuit Paths with Loopbacks
Use loopbacks and hairpin circuits to test newly created SONET circuits before running live traffic or to
logically locate the source of a network failure. All ONS 15454 electrical cards, OC-N cards, G-Series
Ethernet cards, and FC_MR-4 cards allow loopbacks and hairpin test circuits. Other cards do not allow
loopbacks, including E-Series Ethernet, ML-Series Ethernet, and DWDM cards such as Optical Booster
(OPT-BST), Optical Preamplifier (OPT-PRE), Optical Service Channel and Combiner/Splitter Module
(OSC-CSM), Band Optical Add/Drop Multiplexing (AD-xB-xx.x), and Channel Optical Add/Drop
Multiplexing (AD-xC-xx.x) cards. For transponder (TXP) or muxponder (MXP) loopback information,
refer to the Cisco ONS 15454 DWDM Troubleshooting Guide.
To create a loopback on a port, the port must be in the Out-of-Service and Management, Maintenance
(OOS-MA,MT) service state. After you create the loopback, the service state becomes Out-of-Service
and Management, Loopback and Maintenance (OOS-MA,LPBK & MT).
Facility or terminal loopbacks can be service-affecting. To protect traffic, apply a lockout or Force
Caution
switch to the target loopback port. Basic directions for these procedures are in
Troubleshooting."
in the Cisco ONS 15454 Procedure Guide.
Do not use a physical loopback to verify circuit switching time or to determine whether a situation causes
Note
a traffic hit. Testing in this manner can cause a hit that exceeds 60 m/sec. To test switching times, place
a test set at both physical ends of the circuit.
On all OC-N cards, a facility loopback applies to the entire card and not an individual circuit. Exercise
Caution
caution when using loopbacks on an OC-N card carrying live traffic.
Cisco ONS 15454 Troubleshooting Guide, R8.5
1-2
1.7 Using CTC Diagnostics, page
diagnostic file for Cisco Technical Support, and create a bidirectional diagnostic VT circuit.
1.8 Restoring the Database and Default Settings, page
software data and restoring the node to the default setup.
1.9 PC Connectivity Troubleshooting, page
and network connectivity to the ONS 15454.
1.10 CTC Operation Troubleshooting, page
Cisco Transport Controller (CTC) login or operation problems.
1.11 Circuits and Timing, page
and error reporting as well as timing reference errors and alarms.
1.12 Fiber and Cabling, page
connectivity errors.
1.13 Power Supply Problems, page
problems.
For more information about these operations, refer to the "Maintain the Node" chapter
1-107—Explains how to perform card LED tests, download a
1-114—Provides procedures for restoring
1-115—Provides troubleshooting procedures for PC
1-120—Provides troubleshooting procedures for
1-134—Provides troubleshooting procedures for circuit creation
1-139—Provides troubleshooting procedures for fiber and cabling
1-148—Provides troubleshooting procedures for power supply
Chapter 1 General Troubleshooting
Chapter 2, "Alarm
November 2009