I love the PBX analogy for alternative ideas. I mean, what if we were actually working towards a scheme which essentially put one 32 bit address inside another

I love the PBX analogy for alternative ideas. I mean, what if we were actually working towards a scheme which essentially put one 32 bit address inside another, and you explicitly specified gateways? It might work really well for real-world use cases. Say I'm a small business and I sign up with the local cable modem provider and get a static IP address from them: A.A.A.A. Then I have my machines configured inside my network as 10.0.0.1, 10.0.0.2, 10.0.0.3, and so on. Just like now, right? Well, now let's say I want those machines individually addressable from the outside world. We'd need some way to encode that in the headers, and by extension, into things like DNS. serv1.example.com. IN A+ A.A.A.A:10.0.0.1 serv2.example.com. IN A+ A.A.A.A:10.0.0.2 So things change and now I want a second ISP. They also give me a second static IP address: B.B.B.B. I add this as a second gateway and use it to extend the possible ways to reach my machines. serv1.example.com. IN A+ A.A.A.A:10.0.0.1 IN A+ B.B.B.B:10.0.0.1 serv2.example.com. IN A+ A.A.A.A:10.0.0.2 IN A+ B.B.B.B:10.0.0.2 Yep, my same systems are now accessible either way. I just "multi-homed" my network without getting an ASN, setting up BGP and peering, buying a huge router, or any of that. It didn't require any coordination between the ISPs, and I didn't need to get "portable" IP space. Now, obviously, the clients would need to know how to speak this. But hey, the backbone doesn't have to change at all. To the rest of the Internet, it looks like (slightly fatter) packets flying around to A.A.A.A and B.B.B.B. They might have some extra IP options on board (to encode the internal address), but who cares? I'd think this would start showing up in systems which are mass-produced and which nail up a bunch of connections to servers - game consoles, cell phones, that sort of thing. The fact that only the endpoints need to know about it makes it even more obvious. And hey, the servers don't even need to know about this scheme if the gateway manages that for them. (Sound familiar? It's because I wrote about it in April as a "half-baked idea": http://rachelbythebay.com/w/2013/04/22/ipspace/ http://rachelbythebay.com/w/2013/04/22/ipspace/)