The best VPN connections are ones that are made with full bars of cellular service on 3G network cards. Having the best service coverage and fastest possible cellular modem card will ensure a more stable VPN connection.

Cellular networks may also have more latent connections compared to regular land lines. To help account for this, it may be necessary to adjust the amount of time the tunnel connection is left open on the VPN server side or make adjustments to the WAN Alive interval.