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Cisco ONS 15454 SDH Troubleshooting and Maintenance Guide, R3.3
May 2002
Chapter 2 General Troubleshooting
Identify Points of Failure on a Circuit Path
Caution Performing a loopback on an in-service circuit is service-affecting.
Procedure: Create a Facility Loopback Circuit on a Destination E3-12 Card
Step 1 Connect an electrical test set to the port you are testing:
a. Use appropriate cabling to attach the electrical test set transmit (Tx) and receive (Rx) terminals to
the FMEC card connectors or DSx panel for the port you are testing. Both transmit (Tx) and receive
(Rx) connect to the same port.
b. Set up your test set accordingly.
Step 2 Use CTC to create the facility loopback circuit on the port being tested:
a. In node view, double-click the card where the loopback will be performed.
b. Click the Maintenance > Loopback tabs.
c. Select Facility (Line) from the Loopback Type column for the port being tested. If this is a multiport
card, select the row appropriate for the desired port.
d. Click Apply.
e. On the confirmation dialog box, click Yes.
Note It is normal for an alarm to appear during loopback setup. The alarm clears when you remove
the loopback.
Proceed to the “Test the Facility Loopback Circuit” section on page 2-12.
Procedure: Test the Facility Loopback Circuit
Step 1 If the test set is not already sending traffic, send test traffic on the loopback circuit.
Step 2 Examine the test traffic received by the test set. Look for errors or any other signal information that the
test set is capable of indicating.
Step 3 If the test set indicates a good circuit, no further testing is necessary with the loopback circuit.
a. Clear the facility loopback.
b. The entire E3-12 circuit path has now passed its comprehensive series of loopback tests. This circuit
qualifies to carry live traffic.
Step 4 If the test set indicates a faulty circuit, the problem may be a faulty E3-12 card, faulty cabling from the
E3-12 card to the DSx panel or the FMEC card, or a faulty FMEC card.
Proceed to the “Test the E3-12 Cabling” section on page 2-5.
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