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Cisco ONS 15600 SDH Troubleshooting Guide, R8.0
July 2010
Chapter 1 General Troubleshooting
1.1 Network Troubleshooting Tests
•
1.10 Power Supply Problems, page 1-74
—Provides troubleshooting information for common
power supply issues.
1.1 Network Troubleshooting Tests
Use loopbacks to test newly created circuits before running live traffic or to logically locate the source
of a network failure. All ONS 15600 SDH optical (STM-N) cards allow loopbacks.
Caution
On optical cards, a loopback can be applied only if the port state is Locked,maintenance for facility,
terminal, and payload loopbacks, and the circuit state is Locked,maintenance for cross-connect
loopbacks.
Note
Do not use loopbacks to verify circuit switch times or traffic hits because it could exceed 60 msec. For
switch times, a test set should be placed at both ends of the circuits.
Note
When an entity is put in the administrative state, the ONS 15600 SDH suppresses all standing alarms
on that entity. All alarms and events appear on the Conditions tab. You can change this behavior for the
LPBKFACILITY, LPBKPAYLD, and LPBKTERMINAL alarms. To display these alarms on the Alarms
tab, set the NODE.general.ReportLoopbackConditionsOnPortsInLocked,maintenance to TRUE on the
NE Defaults tab.
1.1.1 Facility Loopbacks
The following sections give general information about facility loopback operations and specific
information about ONS 15600 SDH card loopback activity.
1.1.1.1 General Behavior
A facility loopback tests the line interface unit (LIU) of an ASAP card or STM-16 card and related
cabling. After applying a facility loopback on a port, use a test set to run traffic over the loopback. A
successful facility loopback isolates the LIU or the cabling plant as the potential cause of a network
problem. To test an STM-N port or Ethernet port, connect an optical test set to the port and perform a
facility loopback. Alternately, use a loopback or hairpin circuit on a card that is farther along the circuit
path.
Note
CTC sometimes calls a facility loopback a facility (line) loopback. This is done to clarify the direction
that the loopback signal travels, that is, out from the facility toward the span.
shows a facility/payload loopback on an STM-N port.
Summary of Contents for Cisco ONS 15600 SDH
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