Enabling and Disabling Time Jumps

Time-Stamping and Time Synchronization

product_line_custom
IntelĀ® PAC
Napatech SmartNIC
category
User Guide

In this section

This section describes how to enable and disable time jumps.

Time jumps and time resets

When the TimeSyncHardReset parameter is set to ENABLE, time jumps are accepted. The time jump threshold value is 60 ms. If the offset exceeds 60 ms, the time jumps.

When the TimeSyncHardReset parameter is set to DISABLE, time offset adjustment slides into time synchronization, no matter how large the offset is. The maximum slide rate is 2 milliseconds per second.

Note: When using OS time synchronization and merging across multiple SmartNICs, TimeSyncHardReset must be set to DISABLE (sliding mode) to avoid merge errors due to time jumps backwards in time.
Note: When sliding is used, it is recommended, that the timeSyncInSyncStatus parameter in the information stream is monitored from the application and that the clock is reset if required by using the NT_CONFIG_PARM_ADAPTER_TIMESYNC_RESET parameter in the configuration stream with the NT_TIMESYNC_RESET_HARD_RESET_TIME_TO_REF command.
Note: When PTP is used as time synchronization reference, the allowed skew is limited to 38 hours. If the skew exceeds 38 hours, the PTP stack forces a hard reset of the clock irrespective of the setting of TimeSyncHardReset.

ntservice.ini code line

The syntax for the ntservice.ini code line enabling and disabling time jumps is:

'TimeSyncHardReset' '=' ( 'DISABLE' | 'ENABLE' )

Example:

TimeSyncHardReset=DISABLE

Default value

This table shows the default value.

Parameter Default Value
TimeSyncHardReset DISABLE