Snom phones support a VPN feature through the OpenVPN software.
OpenVPN is a very powerful tunnelling solution and offers a wide set of features.
More information on how to set up VPN can be found here: Configuring VPN on Snom Deskphones
One of the most useful and less known feature is the support for multiple remote VPN endpoint. As documented on the main page of the OpenVPN website, you can define more than one remote statement in your vpn.cnf.
Here is a very simple vpn.cnf example using more than one remote endpoint:
client tls-client dev tun proto udp remote server1.foo.com 1194 remote server2.foo.com 1194 remote server3.foo.com 1194 resolv-retry infinite nobind persist-key persist-tun ca /openvpn/myca.crt cert /openvpn/clien.crt key /openvpn/client.key ns-cert-type server ping-restart 60
For more informations and details please check out the official OpenVPN documentation: