Specifications
2-8
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 2 General Troubleshooting
c. If the circuit is now good, the problem was probably the defective card. Replace the suspect card
and return the defective card to Cisco. Call the Technical Assistance Center (TAC) at
1-877-323-7368 to open an RMA case.
Procedure: Perform a Hairpin on a Source Node
The second loopback test is a hairpin circuit performed on the first cross-connect card in the circuit. A
hairpin circuit uses the same port for both source and destination. Completing a successful hairpin
through this card eliminates the possibility that the source cross-connect card is the cause of the faulty
circuit.
Figure 2-6 Hairpin on a source node
Note The ONS 15454 does not support simplex operation on the cross-connect card. Two cross-connect
cards of the same type must be installed for each node.
Step 1 Test the test set with a hard loop if you have not already done so.
To perform a hard loop, bridge the test set transmit (Tx) and receive (Rx) terminals with a cable and send
traffic across this loop to make the test set work.
Step 2 If you just completed the “Perform a Facility Loopback on a Source DS-N Card” procedure on page 2-4,
leave the electrical test set hooked up to the DS-N card.
Step 3 If you are starting the current procedure without the electrical test set hooked up to the DS-N card, use
appropriate cabling to attach the electrical test set transmit (Tx) and receive (Rx) terminals to the EIA
connectors or DSx panel for the port you are testing. Both transmit (Tx) and receive (Rx) connect to the
same port. Set up the test set accordingly.
Step 4 Click the Circuits tab and click the Create button.
Step 5 Give the circuit an easily-identifiable name, such as hairpin1.
Step 6 Set the Circuit Type and Size to your normal preferences.
Step 7 Uncheck the Bidirectional check box and click Next.
Step 8 In the Circuit Source dialog box, fill in the same card and port where you performed the first loopback
test. The DS-N card in the source node.
Step 9 Click Next.
Step 10 In the Circuit Destination dialog box, use the same card and port used for the source information.
Step 11 Click Finish.
DS-N OC-N
XC
ONS 15454
Source
OC-N DS-N
XC
ONS 15454
Destination
DS-N
DS-N
Test Set A
Hairpin
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