MX2800 STS-1 User Manual Status, Section 4
Timing Status
61204659L1-1A 4-7
5. TIMING STATUS
The following entries describe the state of the STS-1 transmit timing subsystem. Information includes the
following:
• Status of the selected reference clock(s)
• Availability and status of the external clock sources
• Timing acquisition status
• Internal clock failures.
Clock Status
This entry describes the condition of the clock synchronization circuitry. The clock status can be any of the
following values shown in Table 4-8.
Current Source
This entry indicates the source of the clock. The values for the clock source are provided in Table 4-9.
Table 4-8. Clock Status
Condition Description
Normal Clock synchronization is operating normally.
Recovering Clock synchronization is in the process of recovering from a fault.
Loss of Source The reference clock source has become invalid.
Out of Range The clock synchronization circuit is unable to track the reference source.
Out of Lock The clock synchronization circuit is unable to lock to the reference source.
Table 4-9. Clock Source
Condition Description
Loop Timing is currently being derived from the STS-1 receive signal.
PRI Ext Timing is currently being derived from the source assigned to the primary exter-
nal clock source.
SEC Ext Timing is currently being derived from the source assigned to the secondary
external clock source.
Free-run Transmit timing is currently being derived from an internal ±20 ppm (Stratum 4)
SONET minimum clock source.
Holdover A failure in the selected clock source has occurred and the unit has entered
hold-over mode. In this mode, the last known good clock reference frequency
will be held within 4.1 ppm for a minimum of 24 hours.
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