VMTP 11.0.2 Napatech Card Clock Drift

Document ID : KB000101445
Last Modified Date : 13/06/2018
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After upgrading the Virtual Multi-Port to 11.0.2, the customer was seeing the Napatech capture card's internal clock drifting out of sync with the server's operating system clock. This drifting eventually lead to the two clocks being far enough from each other that data analysis became inconsistent.
CentOS 6.X
The root cause of this issue was a change in the default sync settings on the Napatech card.

The card was set to 'FreeRun' which isolates the Napatech card's clock from all outside influences.

We were able to see that the card was running in 'FreeRun' mode by accessing the monitoring tool provided by Napatech


Once in this menu, hit 'X' to access the TimeSync menus
**Customer should ensure that all servers are connected to NTP servers**

We want to use the operating system's clock as a reference for the Napatech card's clock.

In order to do this, we need to switch the Napatech card's TimeSync mode to 'OsTime'

To switch modes, we need to do the following:

1) nano /opt/napatech3/config/ntservice.ini

2) You should see 4 or more Napatech Model #s in this file (ex. [NT20E2]). In each card model’s section, we are going to add the following lines: 

TimeSyncConnectorExt1 = None
TimeSyncConnectorInt1 = None
TimeSyncConnectorInt2 = None
TimeSyncReferencePriority = OSTime

3) Once that is complete, Save the file (CTRL-O) and Exit (CTRL-X)

4) Restart the ntservice
a. /opt/napatech3/bin/ntstop.sh
b. /opt/napatech3/bin/ntstart.sh

5) To confirm the updated configuration has been applied:
a. /opt/napatech3/bin/monitoring
b. Hit ‘X’
c. ‘Current Reference’ and ‘Reference Priority’ should show “OsTime”

6) Monitor for drift over the next few days.