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Chapter 1
General Troubleshooting
b.
c.
d.
The circuit qualifies to carry traffic.
1.3 Troubleshooting Optical Circuit Paths With Loopbacks
Facility (line) loopbacks, terminal (inward) loopbacks, and cross-connect loopback circuits are often
used together to test the circuit path through the network or to logically isolate a fault. Performing a
loopback test at each point along the circuit path systematically isolates possible points of failure.
The procedures in this section apply to optical cards. (For instructions on G-Series Ethernet cards, go to
the
information about troubleshooting MXP and TXP cards, go to the
FC_MR Circuit Paths With Loopbacks" section on page
optical circuit on a three-node MS-SPRing. Using a series of facility, cross-connect, and terminal
(inward) loopbacks, the example scenario traces the circuit path, tests the possible failure points, and
eliminates them. The logical progression contains seven network test procedures:
The test sequence for your circuits will differ according to the type of circuit and network topology.
Note
1.
2.
3.
4.
5.
6.
7.
Note
Facility, hairpin, and terminal loopback tests require on-site personnel.
1.3.1 Perform a Facility (Line) Loopback on a Source-Node Optical Port
The facility (line) loopback test is performed on the node source port in the network circuit. In the testing
situation used in this example, the source STM-N port in the source node. Completing a successful
facility (line) loopback on this port isolates the optical port as a possible failure point.
an example of a facility loopback on a circuit source STM-N port.
July 2005
Choose the loopback circuit being tested.
Click Delete.
Click Yes in the Delete Circuits dialog box. Do not check any check boxes.
"1.4 Troubleshooting Ethernet Circuit Paths With Loopbacks" section on page
A facility (line) loopback on the source-node STM-N port
A terminal (inward) loopback on the source-node STM-N port
A cross-connect loopback on the source STM-N port
A facility (line) loopback on the intermediate-node STM-N port
A terminal (inward) loopback on the intermediate-node STM-N port
A facility (line) loopback on the destination-node STM-N port
A terminal (inward) loopback on the destination-node STM-N port
1.3 Troubleshooting Optical Circuit Paths With Loopbacks
"1.5 Troubleshooting MXP, TXP, or
1-80.) The example in this section tests an
Cisco ONS 15454 SDH Troubleshooting Guide, R5.0
1-62. For
Figure 1-19
shows
1-39
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