How to avoid disconnection of a VPN session

The VPN of the multi-wavelength analysis system has a non-communication
timeout of 3 hours.
You can avoid this timeout by communicating in the meantime.

As methods of continuous communication fore more than 3 hours,
you can open a terminal and execute the top command to display
the result continuously, or set ServerAliveInterval in the ssh
client settings.

Alternatively, if you use VNC, you can continue the analysis
even though the VPN is disconnected.