> The "mobile IP" problem isn't IP's job and should not be. IP should be as stateless as possible because this makes it cheap and easy to add capacity and redundancy to a network.
But, to be clear, many implementations of IP (both IPv4 and IPv6) do already have "mobile IPs." There's nothing stopping you from having "mobile IPs." They're just complex, and only work when everywhere the IP can move between all exists within a single AS.
• You can move between multiple wireless APs in a conference hall, and have a layer-3 address that follows you as you switch network segments and thus acquire new layer-2 addresses (which means that the packets destined to that address are being dynamically re-routed at some upstream switch, as the address assignment changes.)
• You can move between cellular antenna and frontend infra (think: WiMax or 5G APs) at different places in a city, while remaining connected to a single cellular backend infra (what you'd think of as a "cell tower") and thus holding a single persistent L3 address.
> You can move between multiple wireless APs in a conference hall, and have a layer-3 address that follows you as you switch network segments and thus acquire new layer-2 addresses (which means that the packets destined to that address are being dynamically re-routed at some upstream switch, as the address assignment changes.)
Is it possible to implement this at home, without paying a lot of money? I've tried it with UniFi AP (with software controller) and no luck :-(
For a house, you probably just want wireless range repeaters/extenders, or mesh APs like these (https://www.wired.com/story/best-mesh-wifi-routers/). Their key advantage being that the backhaul is wireless — you don't have to wire them back to the switch.
If you really want to do an "enterprise" wireless setup, and you want it to be cheap, well... you can buy the relevant equipment (802.11 enterprise wireless APs) used, often in bulk. Sometimes computer recyclers even have them!
Make sure you buy the stuff intended for office buildings, though, not the conference-hall open-plenum equipment. The conference-hall stuff is like studio lighting: powerful at a distance (five-storey hall ceiling down to you on the floor) at the expense of guzzling power and dumping tons of heat.
Also, obviously, unlike the home stuff, with the enterprise hardware, you do need to be able to run an Ethernet backhaul back to a switch somewhere, to join all these APs' L1 collision-domains into a common link-layer network segment. And that switch has to understand what it's doing, so you'd probably need something enterprise-y there, too, unless the state of open-source consumer router firmware has really caught up with enterprise.
Extenders works very badly, as they use 1/2 of bandwidth for themselves and need to be placed twice as often as APs. I have no problem to wire normal APs to switch, as I have several RJ45 sockets in each corner of each room :-)
Now I have one AP per room already, but can not implement seamless transition - when phone/laptop switches to other AP it requests DHCP again and drops all connections. It is very inconvenient.
I know "Buy Cisco's APs for $700/piece and controller for several thousand $$$", I wander why there is no open-source solution (hostapd & Ko), which "secret source" these enterprise solutions include, is it private technology or some open industrial standards, like 802.11[some obscure letter]?
Many expensive APs are built with Linux and hostpad inside, and still doesn't support this feature.
You can actually move anywhere with Mobile IPv6. If you move outside your AS, it automatically tunnels your traffic back to your home network with IPsec. There's also a feature called "Correspondent Node" which allows you to send traffic directly rather than tunnelling via your home network.
Which kind of makes it sound like IPv6 already has the feature the article thinks it should have had.
But, to be clear, many implementations of IP (both IPv4 and IPv6) do already have "mobile IPs." There's nothing stopping you from having "mobile IPs." They're just complex, and only work when everywhere the IP can move between all exists within a single AS.
• You can move between multiple wireless APs in a conference hall, and have a layer-3 address that follows you as you switch network segments and thus acquire new layer-2 addresses (which means that the packets destined to that address are being dynamically re-routed at some upstream switch, as the address assignment changes.)
• You can move between cellular antenna and frontend infra (think: WiMax or 5G APs) at different places in a city, while remaining connected to a single cellular backend infra (what you'd think of as a "cell tower") and thus holding a single persistent L3 address.