Right. XMPP is merely a transport protocol. That solves one very minor problem which can be solved dozens of other ways. The contents of those transport packets

Right. XMPP is merely a transport protocol. That solves one very minor problem which can be solved dozens of other ways. The contents of those transport packets have to make sense between devices. How do you do that? Say you introduce a new device to the network. Whatever magic transport protocol you are using discovers it and your control hub takes ownership after some handshake process. Now, how does the hub—and by implication every other device on the network—know what that new device is and what it can do? It’s a lightbulb? Okay, that’s just on and off right? Oh, no it might have dimming capability. Maybe it’s a candelabra with multiple bulbs? Maybe the bulb can show different colors. Maybe it has a wake-up gradual brightening process built in. Maybe it has a sensor built in to adjust brightness and color temperature based on existing light sources. Maybe you want to disable that but also set the color to purple. How do you exchange all this capability information? And this is just a lightbulb. XMPP federation doesn’t solve for that.