Description: The administrative timing source for the ERX system. The ERX periodically monitors the status of three timing sources, primary, secondary and tertiary. If the systems current timing source fails, the system will automatically downgrade to the next timing source. If the system is configured to automatically upgrade (usdERXSysTimingDisableAutoUpgrade is set to false(2)) the system will switch back to the higher timing source when it becomes available.

A timing source failure can be detected by comparing the operational and admin timing sources. If they are not equal, the system has swapped timing sources because the administratively set value is in the error state.