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Chapter 1
General Troubleshooting
c.
d.
If the tests indicate further problems, go to the
Step 7
Destination Electrical Port (West to East)" procedure on page
1.2.4 Perform a Terminal (Inward) Loopback on a Destination Electrical Port
(West to East)
The terminal (inward) loopback test is performed on the node destination port in the circuit, such as a
destination-node electrical port. You first create a bidirectional circuit that starts on the source-node 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 up to the destination port.
E1-N-14 port.
Figure 1-14
Test Set
Performing a loopback on an Unlocked circuit is service-affecting. To protect traffic, apply a lockout or
Caution
Force switch to the target loopback port. For more information on these operations, refer to the
Cisco ONS 15454 SDH Procedure Guide Chapter 15, "Maintain the Node."
Electrical circuit terminal loopbacks do not transmit an AIS condition in the direction away from the
Note
loopback. Instead of an AIS, a continuance of the signal transmitted to the loopback is provided.
Complete the
page
Create the Terminal (Inward) Loopback on a Destination Electrical Port
Connect an electrical test set to the port you are testing:
Step 1
a.
July 2005
1.2.4 Perform a Terminal (Inward) Loopback on a Destination Electrical Port (West to East)
Click Delete.
Click Yes in the Delete Circuits dialog box. Do not check any check boxes.
Terminal (Inward) Loopback on a Destination E1-N-14 Port
Source
ONS Node
E3-12
"Create the Terminal (Inward) Loopback on a Destination Electrical Port" procedure on
1-21, then test and clear the loopback as instructed.
If you just completed the
"1.2.3 Perform an XC Loopback on a Destination-Node STM-N VC (West
to East) Carrying an Electrical Signal" procedure on page
up to the source-node port.
"1.2.4 Perform a Terminal (Inward) Loopback on a
Figure 1-14
shows an example of a terminal loopback on a destination
XC
STM-N
Cisco ONS 15454 SDH Troubleshooting Guide, R5.0
1-21.
Destination
ONS Node
STM-N
XC
E3-12
1-17, leave the electrical test set hooked
1-21
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