Foo over UDP

For example with mobile networking I can setup a laptop or smartphone to use a 'tinc'-based VPN. This allows for more of a 'mesh' style VPN networking rather then a traditional 'hub and spoke' style networking. Tunnels can be setup to work on a best-effort basis. So if I am on my private network it connects to the vpn to internal addresses, when I am on a public network it connects to the public points I have setup. It can use udp or tcp, etc etc.

What this gets me (at least in theory) is then a continuous, persistent, private network connection regardless of were I am at. That way I, although it isn't perfect, can keep a persistent network connection for things like ssh and whatnot. I don't end up using it a whole lot this way, but it's pretty handy.

Tunneling can actual alleviate a whole host of issues associated with TCP/IP style networking. Just like with virtual machines separating the logical from the physical has it's own benefits.