Cisco Systems ONS 15327 manual Holdover Synchronization Alarm, Free-Running Synchronization Mode

Chapter 1 General Troubleshooting

Circuits and Timing

1.7.7 Holdover Synchronization Alarm

Symptom The clock is running at a different frequency than normal and the HLDOVRSYNC alarm appears.

Table 1-31describes the potential cause of the symptom and the solution.

Table 1-31 Holdover Synchronization Alarm

Possible Problem	Solution
The last reference input	The clock is running at the frequency of the last valid reference input. This
has failed.	alarm is raised when the last reference input fails. See the
	“2.6.94 HLDOVRSYNC” section on page 2-73for a detailed description of
	this alarm.
	Note The ONS 15327 supports holdover timing per Telcordia GR-4436
	when provisioned for external (BITS) timing.

1.7.8 Free-Running Synchronization Mode

Symptom The clock is running at a different frequency than normal and the FRNGSYNC alarm appears.

Table 1-32describes the potential cause of the symptom and the solution.

Table 1-32 Free-Running Synchronization Mode

Possible Problem	Solution
No reliable reference	The clock is using the internal oscillator as its only frequency reference. This
input is available.	occurs when no reliable, prior timing reference is available. See the
	“2.6.90 FRNGSYNC” section on page 2-71for a detailed description of this
	alarm.

1.7.9 Daisy-Chained BITS Not Functioning

Symptom You are unable to daisy-chain the BITS.

Table 1-33describes the potential cause of the symptom and the solution.

Table 1-33 Daisy-Chained BITS Not Functioning

Possible Problem	Solution
Daisy-chaining BITS is	Daisy-chaining BITS causes additional wander buildup in the network and
not supported on the	is therefore not supported. Instead, use a timing signal generator to create
ONS 15327.	multiple copies of the BITS clock and separately link them to each
	ONS 15327.

Cisco ONS 15327 Troubleshooting Guide, R3.4

1-70 April 2003