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Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 12 Maintenance
Network Test Procedures
Figure 12-12 The terminal loopback process on an OC-N card
12.10 Network Test Procedures
Facility loopbacks, hairpin circuits and terminal loopbacks are often used together to test the circuit path
through the network or to logically isolate a fault. Performing a network test at each point along the
circuit path systematically eliminates possible points of failure. This example tests an XTC circuit on a
two-node bidirectional line switched ring (BLSR). Using a series of facility loopbacks, hairpin circuits,
and terminal loopbacks, the path of the circuit is traced and the possible points of failure eliminated.
A logical progression of five network test procedures apply to this scenario:
1.
A facility loopback on the source-node XTC card,
2.
A hairpin on the source-node XTC card,
3.
A hairpin on the destination-node OC-N card,
4.
A terminal loopback to the destination-node XTC card, and
5.
A facility loopback to the destination XTC card.
Note
These procedures are performed when power connections to the node(s) or site(s) are assumed to be
within necessary specifications. If the network tests do not isolate the problems, troubleshoot
outward for power failure.
12.10.1 Perform a Facility Loopback on a Source XTC Card
The first test is a facility loopback test performed on the first active card in the network circuit; in this
example, the test is routed through the MIC card and performed on the XTC card in the source node.
Completing a successful facility loopback on this card eliminates the cabling, MIC card, and XTC card
as possible failure points.
DS-N
MIC
OC-N
DS-N
Test Set A
Terminal loopback
XTC
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Summary of Contents for ONS 15327
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Page 30: ...Figures xxviii Cisco ONS 15327 User Documentation June 2002 ...
Page 44: ...Procedures xlii Cisco ONS 15454 Installation and Operations Guide R3 2 June 2002 ...
Page 540: ...Glossary GL 16 Cisco ONS 15327 User Documentation R3 3 June 2002 ...