Oc-3 And Dcc Limitations; Holdover Synchronization Alarm - Cisco ONS 15454 Troubleshooting Manual

1.9.6 OC-3 and DCC Limitations

1.9.6 OC-3 and DCC Limitations
Symptom
Table 1-32
Table 1-32 OC-3 and DCC Limitations
Possible Problem
OC-3 and DCC have
limitations for the
ONS 15454.
1.9.7 ONS 15454 Switches Timing Reference
Symptom
Table 1-33
Table 1-33 ONS 15454 Switches Timing Reference
Possible Problem
The optical or BITS input is receiving loss of signal (LOS),
loss of frame (LOF), or AIS alarms from its timing source.
The optical or building integrated timing supply (BITS)
input is not functioning.
The synchronization status messaging (SSM) message is
set to do not use for synchronization (DUS).
SSM indicates a Stratum 3 or lower clock quality.
The input frequency is off by more than 15 ppm.
The input clock wanders and has more than three slips in
30 seconds.
A bad timing reference existed for at least two minutes.

1.9.8 Holdover Synchronization Alarm

Symptom
appears.
Table 1-34
Cisco ONS 15454 Troubleshooting Guide, R4.6
1-92
Limitations to OC-3 and DCC usage.
describes the possible problem and the solution.
Solution
For an explanation of OC-3 and DCC limitations, refer to the DCC Tunnels
section of the Cisco ONS 15454 Procedure Guide.
Timing references switch when one or more problems occur.
describes the possible problems and the solution.
The clock is running at a different frequency than normal and the
describes the possible problem and the solution.
Chapter 1 General Troubleshooting
Solution
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
–7
24 hours or 3.7 x 10 /day, including
temperature.
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.
"HLDOVRSYNC" alarm
November 2004