2-28
Cisco ONS 15454 SDH Troubleshooting and Maintenance Guide, R3.3
May 2002
Chapter 2 General Troubleshooting
Circuits and Timing
2.4.1 TU-AIS on Unused VC Circuits
Symptom An incomplete circuit path causes a tributary unit alarm indications signal (TU-AIS).
Table 2-16 describes the potential cause(s) of the symptom and the solution(s).
Procedure: Clear TU-AIS on Unused VC Circuits
Step 1 Determine the affected port.
Step 2 Record the node ID, slot number, port number, or VC number.
Step 3 Create a unidirectional VC circuit from the affected port back to itself, such as Source node/Slot 2/Port
2/VC11 cross connected to Source node/Slot 2/Port 2/VC11.
Step 4 Uncheck the bidirectional box in the circuit creation window.
Step 5 Give the unidirectional VC circuit an easily recognizable name, such as delete me.
Step 6 Display the DS3IN card in CTC card view. Click the Maintenance > DS1 tabs.
Step 7 Locate the VC that is reporting the alarm (for example, DS3 #2, DS1 #13).
Step 8 From the Loopback Type list, choose Facility (line) and click Apply.
Step 9 Click Circuits.
Step 10 Find the one-way circuit you created in Step 2. Select the circuit and click Delete.
Step 11 Click Yes in the Delete Confirmation box.
Step 12 Display the DS3IN card in CTC card view. Click Maintenance > DS1.
Step 13 Locate the VC in Facility (line) Loopback.
Step 14 From the Loopback Type list, choose None and then click Apply.
Step 15 Click the Alarm tab and verify that the TU-AIS alarms have cleared.
Step 16 Repeat this procedure for all the TU-AIS alarms on the DS3IN cards.
Table 2-16 TU-AIS on Unused VC Circuits
Possible Problem Solution
The port on the
reporting node is
in-service but a node
upstream on the circuit
does not have an
STM-N port in service.
A TU-AIS indicates that an upstream failure occurred at the virtual channel
(VC) layer. TU-AIS alarms also occur on VC circuits that are not carrying
traffic and on stranded bandwidth.
Perform the “Clear TU-AIS on Unused VC Circuits” section on page 2-28.
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