1-68
Cisco ONS 15454 Troubleshooting Guide, R8.5
November 2009
Chapter 1 General Troubleshooting
1.5 Troubleshooting Ethernet Circuit Paths With Loopbacks
b. Choose the loopback circuit being tested.
c. Click Delete.
d. Click Yes in the Delete Circuits dialog box. Do not check any check boxes.
The entire circuit path has now passed its comprehensive series of loopback tests. This circuit
qualifies to carry live traffic.
Step 5 If the test set indicates a faulty circuit, the problem might be a faulty card.
Step 6 Complete the “Test the Optical Card” procedure on page 1-68.
Test the Optical Card
Step 1 Complete the “Physically Replace a Traffic Card” procedure on page 2-273 for the suspected bad card
and replace it with a known-good card.
Step 2 Resend test traffic on the loopback circuit with a known-good card.
Step 3 If the test set indicates a good circuit, the problem was probably the defective card. Return the defective
card to Cisco through the RMA process. Contact Cisco Technical Support at 1 800 553-2447.
Step 4 Complete the “Physically Replace a Traffic Card” procedure on page 2-273 for the defective card.
Step 5 Clear the terminal loopback on the port:
a. Double-click the source-node card with the terminal loopback.
b. Click the Maintenance > Loopback > Port tabs.
c. Select None from the Loopback Type column for the port being tested.
d. Select the appropriate state (IS; OOS,DSBLD; OOS,MT; IS,AINS) in the Admin State column for
the port being tested.
e. Click Apply.
f. Click Yes in the confirmation dialog box.
Step 6 Clear the terminal loopback circuit:
a. Click the Circuits tab.
b. Choose the loopback circuit being tested.
c. Click Delete.
d. Click Yes in the Delete Circuits dialog box. Do not check any check boxes.
The entire circuit path has now passed its comprehensive series of loopback tests. This circuit qualifies
to carry live traffic.
1.5 Troubleshooting Ethernet Circuit Paths With Loopbacks
Facility loopbacks, terminal loopbacks, and cross-connect loopback circuits are often used together to
test the circuit path through the network or to logically isolate a fault. Performing a loopback test at each
point along the circuit path systematically isolates possible points of failure.