1-19
Cisco ONS 15327 Troubleshooting Guide, R3.4
April 2003
Chapter1 General Troubleshoo ting Identify Points of Failure on a DS-N Circuit Path
Step 3 Proceed to the “Test the Facility Loopback Circuit” procedure on page 1-19.
Procedure: Test the Facility Loopback Circuit
Step 1 If the test set is not already sending traffic, send test-set 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:
•Click the Maintenance > Loopback tabs.
•Choose None from the Loopback Type column for the port being tested.
•Choose the appropriate state (IS, OOS, or OOS_AINS) from t he State column f or the port b eing
tested.
•Click the Apply button.
•Click the Yes button in the Con firmatio n Di al og box .
b. The entire DS-N 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 might be a faulty MIC card or faulty cabling from
the MIC card to the XTC card.
Step 5 Proceed to the “Test the DS-N Cabling” procedure on page1-6.
Procedure: Test the DS-N Cabling
Step 1 Replace the suspect cabling (the cables from the test set to the MIC ports) with a good cable.
If a good cable is not available, test the suspect cable with a test set. Remove th e s uspec t cab le f ro m the
MIC and connect the cable to the Tx and Rx terminals of the test set. Run traffic to determine whether
the cable is good or suspect.
Step 2 Resend test traffic on the loopback circuit with a good cable installed.
Step 3 If the test set indicates a good circuit, the problem is probably the defective cable:
a. Replace the defective cable.
b. Clear the facility loopback:
•Click the Maintenance > Loopback tabs.
•Choose None from the Loopback Type column for the port being tested.
•Choose the appropriate state (IS, OOS, or OOS_AINS) from t he State column f or the port b eing
tested.
•Click the Apply button.
•Click the Yes button in the Con firmatio n Di al og box .