VPNTTG is able to poll many devices parallel, making operations far quicker.
For this feature it is necessary to have a license key with unlimited VPN tunnels and to edit the /etc/cron.d/vpnttg crontab file as shown below:

* * * * *     root    /stats/vpnttg/bin/vpnttg1       > /dev/null 2>&1
* * * * *     root    /stats/vpnttg/bin/vpnttg2       > /dev/null 2>&1
* * * * *     root    /stats/vpnttg/bin/vpnttg3       > /dev/null 2>&1
* * * * *     root    /stats/vpnttg/bin/vpnttg4       > /dev/null 2>&1

Where /stats/vpnttg/bin/vpnttg1, /stats/vpnttg/bin/vpnttg2 and so on are symbolic links of the /stats/vpnttg/bin/vpnttg file.

The /stats/vpnttg/bin/vpnttg file is responsible to poll all devices sequentially.
However
The /stats/vpnttg/bin/vpnttg1 file is responsible to poll only first device.
The /stats/vpnttg/bin/vpnttg2 file is responsible to poll only second device.
And so on.