1-10
Cisco ONS 15310-CL and Cisco ONS 15310-MA Troubleshooting Guide, R7.0
Chapter1 General Troubleshooting
1.2.4 Perform a Hairpin Test on a Destination-Node Port
Step3 If the test set indicates a good circuit, no further testing is necessary on the loopback circuit. Clear the
terminal loopback:
a. Double-click the 15310-CL-CTX or CTX2500 in the destination node with the terminal loopback.
b. Double-click the appropriate card containing the electrical circuit you are testing, and click the
appropriate tab:
•Maintenance > DS1 > Loopback
•Maintenance > DS3 > Loopback
•Maintenance > EC1 > Loopback
c. Select None from the Loopback Type column for the port being tested.
d. Select the appropriate state (IS,AINS,AINS OOS,DSBLD or OOS,MT) in the Admin State column
for the port being tested.
e. Click Apply.
f. Click Yes in the confirmation dialog box.
Step4 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.
Step5 If the test set indicates a faulty circuit, the problem might be a faulty port. Continue with the
“1.2.4 Perform a Hairpin Test on a Destination-Node Port” procedure on page 1-10.
1.2.4 Perform a Hairpin Test on a Destination-Node Port
The hairpin test is performed on the port in the destination node. To perform this test, you must also
create a bidirectional circuit in the transmit direction from the destination ONS15310-CL or
ONS 15310-MA to the source node. Creating the bidirectional circuit and completing a successful
hairpin eliminates the possibility that the source port, destination port, or fiber span is responsible for
the faulty circuit.

Create the Hairpin Loopback Circuit on the Destination-Node Port

Step1 Connect an electrical test set to the electrical port you are testing.
Use appropriate cabling to attach the Tx and Rx terminals of the electrical test set to the electrical cabling
panel for the port you are testing.
Step2 Adjust the test set accordingly.
Step3 Use CTC to set up the source loopback circuit on the port being tested:
a. Click the Circuits tab and click Create.
b. Give the circuit an easily identifiable name, such as Hairpin1.
c. Set the circuit Type and Size to the normal preferences, such as STS and STS1.
d. Leave the Bidirectional check box checked and click Next.