Symmetricom 1000, 1100 manual Controlling Automatic Reference Switching, CCS D4 ESF, JCC JCC4

Chapter 4 Provisioning the TimeProvider

Provisioning the Input Reference

<aid>	<keyword>	<value>	Description	Default value
INPp	FRMTYPE	2M (2.048 MHz) CAS	Provisions the frame	2M (E1)
p = 1 2		CCS D4 ESF	signal type used by	ESF (T1)
		1.544M 6.312M CC	the input.
		JCC JCC4

Sample Command

ED-SYNC::INP1:TS1000::FRMTYPE=ESF;

Autonomous Message

TP-SSU 03-10-24 10:50:05 A 1181 REPT EVT

“INP1,T1:NA,FRMTYPE,NSA,03-10-24 10-50-05:\"INPUT FRAMING TYPE HAS CHANGED,ESF\””

;

Controlling Automatic Reference Switching

The TimeProvider can determine which input reference signal has the highest quality. When the active reference signal falls below a preset quality level, the TimeProvider can automatically switch to the next highest input reference signal. To use this feature, you must enable Automatic switching.

You can also use the performance monitoring features to automatically switch the input reference signal when user-defined performance thresholds are crossed. See Setting MTIE and FFOFF Thresholds, on page 116 for more information on setting and using performance monitoring commands.

Automatic Return to a Higher Priority Reference

When the REFMODE parameter is provisioned to AUTO, the system reference switches when the input signal is disqualified. When the input signal is re-qualified, the TimeProvider can either keep the current reference or switch back to the re-qualified signal. The first case, keeping the current reference, is also known as “non-revertive” mode; the second case, switching back to the re-qualified input, is known as revertive mode.

The QLEVEL (see Setting the Input Quality Level, on page 112) and the PRIORITY (see Setting the Input Priority Level, on page 113) parameters work together with SSMs to determine the switching strategy for the inputs when the unit is in the SSU mode. If the active/primary input becomes unavailable, the switching strategy determines which input to use: the TimeProvider uses the input with the next highest QLEVEL. If all inputs have the same QLEVEL, then the TimeProvider uses the input with the highest PRIORITY.

To provision the TimeProvider as non-revertive, you must provision the user-assigned Priority Level on all inputs to the same value (1, 2, 3, or 4). To provision the TimeProvider as revertive, you provision any one of the inputs to a higher or lower Priority Level, with 1 being the highest priority.

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