Cisco ONS 15454 Troubleshooting Manual page 32

1.3.8 Perform a Terminal (Inward) Loopback on a Source DS-N Port (East to West)
If the test set indicates a faulty circuit, the problem is probably the defective card. Return the defective
Step 3
card to Cisco through the RMA process. Contact Cisco TAC (1 800 553-2447) and proceed to
the circuit is not shown to be faulty and the card is not shown to be defective, you are finished with
testing.
Step 4 Complete the
cross-connect card and perform
If the test set indicates a good circuit, the cross-connect card might have had a temporary problem that
Step 5
was cleared by the side switch. Clear the XC loopback circuit:
a.
b.
c.
d.
1.3.8 Perform a Terminal (Inward) Loopback on a Source DS-N Port (East to
West)
The terminal (inward) loopback test is performed on the node source port in the circuit, such as a source
node DS-N port. You first create a bidirectional circuit that starts on the destination node DS-N port and
loops back on the source node DS-N port. Then you proceed with the terminal loopback test. Completing
a successful terminal loopback to a source node DS-N port verifies that the circuit is good to the source
DS-N.
Figure 1-17 Terminal (Inward) Loopback on a Source DS-N Port
Source
ONS Node
OC-N
Test Set
Performing a loopback on an in-service circuit is service-affecting. To protect traffic, apply a lockout or
Caution
Force switch to the target loopback port. For more information about these operations, refer to the
Cisco ONS 15454 Procedure Guide.
Note DS-3 terminal loopbacks do not transmit an AIS condition in the direction away from the loopback.
Instead of a DS-3 AIS, a continuance of the signal transmitted to the loopback is provided.
Cisco ONS 15454 Troubleshooting Guide, R4.6
1-32
"Replace an In-Service Cross-Connect Card" procedure on page 3-2
Click the Circuits tab.
Choose the XC loopback circuit being tested.
Click Delete.
Click Yes in the Delete Circuits dialog box.
Figure 1-17 shows an example of a terminal loopback on a source DS-N port.
XC OC-N
Step 5.
Intermediate
ONS Node
OC-N XC OC-N
Chapter 1 General Troubleshooting
Step
for the defective
Destination
ONS Node
OC-N XC OC-N
November 2004
4. If