Specifications
CHAPTER
2-1
Cisco ONS 15454 SDH Troubleshooting and Maintenance Guide, R3.3
May 2002
2
General Troubleshooting
This chapter provides procedures for troubleshooting the most common problems encountered when
operating a Cisco ONS 15454 SDH. To troubleshoot specific ONS 15454 SDH alarms, see Chapter 1,
“Alarm Index.” If you cannot find what you are looking for in this chapter or Chapter 1, “Alarm Index,”
contact the Cisco Technical Assistance Center (TAC) at 1-800-553-2447 or login to
http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml to obtain a directory of Cisco TAC
toll-free numbers for your country to obtain more information.
This chapter begins with the following sections on network problems:
• Network Troubleshooting Tests—Describes loopbacks and hairpin circuits, which you can use to
test circuit paths through the network or logically isolate faults.
• Identify Points of Failure on a Circuit Path—Explains how to perform the tests described in the
“Network Troubleshooting Tests” section.
The remaining sections describe symptoms, problems, and solutions that are categorized according to
the following topics:
• CTC Operation and Connectivity—Provides troubleshooting procedures for CTC log-in or
operation errors and PC and network connectivity.
• Circuits and Timing—Provides troubleshooting procedures for circuit creation, error reporting, and
timing reference errors and alarms.
• Fiber and Cabling—Provides troubleshooting procedures for fiber and cabling connectivity errors.
2.1 Network Troubleshooting Tests
Use loopbacks and hairpins to test newly created circuits before running live traffic or to logically locate
the source of a network failure. All ONS 15454 SDH line (traffic) cards, except Ethernet cards, allow
loopbacks and hairpins.
Caution On multiport STM-N cards, a loopback applies to the entire card and not an individual circuit.
Exercise caution when using loopbacks on an STM-N card carrying live traffic.
A facility loopback tests the line interface unit (LIU) of a card, the FMEC, and related cabling. After
applying a facility loopback on a card, use a test set to run traffic over the loopback. A successful facility
loopback eliminates the LIU, FMEC, or cabling as the potential cause of a network problem. Figure 2-1
shows a facility loopback on a E3-12 card.