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Cisco ONS 15454 Troubleshooting Guide, R8.5
November 2009
Chapter 1 General Troubleshooting
1.2.4 Perform a Terminal Loopback on a Destination Electrical Port (West to East)
Step 5 If the test set indicates a good circuit, the cross-connect card might have had a temporary problem that
was cleared by the side switch. Clear the XC loopback circuit:
a. Click the Circuits tab.
b. Choose the XC loopback circuit being tested.
c. Click Delete.
d. Click Yes in the Delete Circuits dialog box. Do not check any check boxes.
Step 6 If the tests indicate further problems, go to the “1.2.4 Perform a Terminal Loopback on a Destination
Electrical Port (West to East)” procedure on page 1-22.
1.2.4 Perform a Terminal Loopback on a Destination Electrical Port (West to
East)
The terminal loopback test is performed on the destination-node electrical port in the circuit, such as a
destination-node electrical port. You create a bidirectional circuit that starts on the source-node electrical
port and loops back on the destination-node electrical port. Then you proceed with the terminal loopback
test. Completing a successful terminal loopback to a destination-node electrical port verifies that the
circuit is good to the destination electrical port. Figure 1-14 shows an example of a terminal loopback
on a destination DS-N port.
Figure 1-14 Terminal Loopback to a Destination DS-N Port
Caution Performing a loopback on an in-service circuit is service-affecting. To protect traffic, apply a lockout or
Force switch to the target loopback port. For more information about these operations, refer to the
“Maintain the Node” chapter in the Cisco ONS 15454 Procedure Guide.
Caution In terminal loopback mode, DS3E-12 card does not support sending AIS toward the line side while
looping back traffic at the same time, though NE defaults are the same.
Note Terminal loopbacks require on-site personnel.
Source
ONS Node
Destination
ONS Node
55265
Test Set
XCDS-N OC-N DS-NXCOC-N
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