Network Test Procedures; Perform A Facility Loopback On A Source Xtc Card; Figure 12-12 The Terminal Loopback Process On An Oc-N Card - Cisco ONS 15327 User Documentation

Chapter 12 Maintenance

Figure 12-12 The terminal loopback process on an OC-N card

Test Set A

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.
2.
3.
4.
5.
These procedures are performed when power connections to the node(s) or site(s) are assumed to be
Note
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.
June 2002
XTC
DS-N
MIC
DS-N
A facility loopback on the source-node XTC card,
A hairpin on the source-node XTC card,
A hairpin on the destination-node OC-N card,
A terminal loopback to the destination-node XTC card, and
A facility loopback to the destination XTC card.
Terminal loopback
OC-N
Cisco ONS 15327 User Documentation, R3.3
Network Test Procedures
12-21