1-19
Cisco ONS 15327 Troubleshooting Guide, R3.4
April 2003
Chapter 1 General Troubleshooting
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 the State column for the port being
tested.
• Click the Apply button.
• Click the Yes button in the Confirmation Dialog 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 page 1-6.
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 the suspect cable from 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 the State column for the port being
tested.
• Click the Apply button.
• Click the Yes button in the Confirmation Dialog box.
