Specifications

2-7
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 2 General Troubleshooting
To perform a hard loop, bridge the test set transmit (Tx) and receive (Rx) terminals with an appropriate
cable and send traffic across the loop to ensure the test set works.
Step 2 If you are starting the current procedure with the electrical test set hooked up to the DS-N card in the
source node, leave the test set hooked up.
Step 3 If you are starting the current procedure without the electrical test set hooked up to the DS-N card in the
source node, 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) cables 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 DSNtoDSN.
Step 6 Set Circuit Type and Size to your normal preferences.
Step 7 Leave the Bidirectional check box checked 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 DS-N card and port in the destination node.
Step 11 Click Finish.
Step 12 Confirm that the newly created circuit appears on a Circuits screen row with a direction column that
shows a 2-way circuit.
Step 13 In node view, double-click the card that requires the loopback. In this example, the DS-N card in the
destination node.
Step 14 Click the Maintenance > Loopback tabs.
Step 15 On the Loopback subtab, select Terminal (Inward) from the Loopback Type column. If this is a
multiport card, such as the OC3 IR 4 1310, make sure to select the row appropriate for the desired port.
Step 16 Click Apply.
Step 17 On the confirmation dialog box, click Yes .
Note Loopbacks operate only on in-service ports.
Note It is normal for an alarm to appear during a loopback setup. The alarm clears when you
remove the loopback.
Step 18 If the test set is not already sending traffic, send test set traffic on the loopback circuit.
Step 19 Examine the test traffic being received by the test set. Look for errors or any other signal information
that the test set is capable of indicating.
Step 20 If the test set indicates a good circuit, proceed to the “Perform a Hairpin on a Source Node” procedure
on page 2-8.
Step 21 If the test traffic is not received or is poor quality, then test the DS-N card.
a. Replace the suspect card with a known good card.
b. Resend test set traffic on the loopback circuit with a known good card.