2-110
Cisco ONS 15327 Troubleshooting Guide, R3.4
March 2004
Chapter2 Alarm Troubleshooting
Alarm Procedures
Step 5 If the signal is valid, verify that the power level of the optical signal is within the optical car d’s receiver
specifications. Refer to the CiscoONS 15327 Reference Manual for card specifications.
Step 6 If the receiver levels are correct, ensure that the optical transmit and receive fibers are connected
properly.
Step 7 If the connectors are correct, complete the “Physically Replace a Card” procedure on page2-130 for th e
OC-N card.
Note When replacing a card with an identical type of card, no additional CTC provisioning is
required.
Step 8 If the condition does not clear, log onto http://www.cisco.com/tac for more information or call TAC
(1-800-553-2447).
2.6.159 SSM-DUS
•Not Alarmed (NA), Non-Service Affecting (NSA)
The Synchronization Status Message (SSM) Quality Changed to Do-Not-Use (DUS) condition occurs
when the synchronization status message (SSM) quality level degrades to DUS or is manually changed
to DUS.
The signal is often manually changed to DUS to prevent timing loops from occurring. Sending a DUS
prevents the timing from being reused in a loop. The DUS signal can also be sent for line maintenance
testing.
Note SSM-DUS is an informational condition. It does not require troubleshooting.
2.6.160 SSM-FAIL
•Minor (MN), Non-Service Affecting (NSA)
The SSM Failed (SSM-FAIL) alarm occurs when the synchronization status messaging received by the
ONS 15327 fails. The problem is external to ONS 15327. The ONS 15327 is set up to receive SSM, but
the timing source is not delivering valid SSM messages.

Procedure: Clear the SSM-FAIL Alarm

Step 1 Verify that SSM is enabled on the external timing source.
Step 2 If timing is enabled, use an optical test set to determine that the external timing source is delivering SSM.
For specific procedures to use the test set equipment, consult the manufacturer.
If the alarm does not clear, log onto http://www.cisco.com/tac for more information or call TAC
(1-800-553-2447).