Cisco ONS 15454 Troubleshooting Manual page 182
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Also See for ONS 15454:
- Procedure manual (850 pages) ,
- Reference manual (728 pages) ,
- Software feature and configuration manual (232 pages)
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1.11.6 OC-3 and DCC Limitations
1.11.6 OC-3 and DCC Limitations
Symptom
1.11.7 ONS 15454 Switches Timing Reference
Symptom
1.11.8 Holdover Synchronization Alarm
Symptom
appears.
Cisco ONS 15454 Troubleshooting Guide, R8.5
1-138
Limitations to OC-3 and DCC usage.
Possible Cause
OC-3 and DCC have limitations for the ONS 15454.
For an explanation of OC-3 and DCC limitations, refer to the "Circuits and
Recommended Action
Tunnels" chapter in the Cisco ONS 15454 Reference Manual.
Timing references switch when one or more problems occur.
The optical or BITS input is receiving loss of signal (LOS), loss of frame (LOF), or
Possible Cause
AIS alarms from its timing source.
The optical or building integrated timing supply (BITS) input is not functioning.
Possible Cause
The synchronization status messaging (SSM) message is set to Do Not Use for
Possible Cause
Synchronization (DUS).
SSM indicates a Stratum 3 or lower clock quality.
Possible Cause
The input frequency is off by more than 15 ppm.
Possible Cause
The input clock wanders and has more than three slips in 30 seconds.
Possible Cause
A bad timing reference existed for at least two minutes.
Possible Cause
Recommended Action
The ONS 15454 internal clock operates at a Stratum 3E level of accuracy. This
gives the ONS 15454 a free-running synchronization accuracy of +/– 4.6 ppm and a holdover
stability of less than 255 slips in the first 24 hours or 3.7 x 10
ONS 15454 free-running synchronization relies on the Stratum 3 internal clock. Over an extended
time period, using a higher quality Stratum 1 or Stratum 2 timing source results in fewer timing slips
than a lower quality Stratum 3 timing source.
The clock is running at a different frequency than normal and the
Possible Cause
The last reference input has failed.
The clock is running at the frequency of the last known-good reference input.
Recommended Action
This alarm is raised when the last reference input fails. See the
page 2-126
for a detailed description.
Chapter 1
General Troubleshooting
–7
/day, including temperature.
"HLDOVRSYNC" alarm
"HLDOVRSYNC" alarm on
November 2009
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