Cisco ONS 15454 Troubleshooting Manual page 22

1.3.5 Perform a Facility (Line) Loopback on a Destination DS-N Port (East to West)
1.3.5 Perform a Facility (Line) Loopback on a Destination DS-N Port (East to
West)
The facility (line) loopback test is performed on the node destination port in the network circuit, in this
example, the DS-N port in the destination node. Completing a successful facility (line) loopback on this
port isolates the cabling, the DS-N card, and the EIA as possible failure points.
example of a facility loopback on a destination DS-N port.
Figure 1-14 A Facility (Line) Loopback on a Circuit Destination DS-N Port
DS-N
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
Cisco ONS 15454 Procedure Guide.
DS-3 facility (line) loopbacks do not transmit an alarm indication signal (AIS) condition in the direction
Note
away from the loopback. Instead of a DS-3 AIS, a continuance of the signal transmitted to the loopback
is provided.
Create the Facility (Line) Loopback on the Destination DS-N Port
Connect an electrical test set to the port you are testing.
Step 1
Use appropriate cabling to attach the Tx and Rx terminals of the electrical test set to the EIA connectors
or DSx panel for the port you are testing. The Tx and Rx terminals connect to the same port. Adjust the
test set accordingly.
In CTC node view, double-click the DS-N card to open the card view.
Step 2
Depending upon the card type, click the Maintenance > Loopback tabs, Maintenance > DS1 tabs, or
Step 3
Maintenance > DS3 tabs.
Choose OOS_MT from the State column for the port being tested. If this is a multiport card, select the
Step 4
appropriate row for the port being tested.
Choose Facility (Line) from the Loopback Type column for the port being tested. If this is a multiport
Step 5
card, select the appropriate row for the port being tested.
Click Apply.
Step 6
Click Yes in the confirmation dialog box.
Step 7
Cisco ONS 15454 Troubleshooting Guide, R4.6
1-22
Source
ONS Node
XC OC-N
Destination
ONS Node
OC-N XC DS-N
Chapter 1 General Troubleshooting
Figure 1-14 shows an
Test Set
November 2004