Matter came around after I left, but I believe it is the same as CHIP: * IEEE 802.15.4 (2.4 GHz PHY/MAC) * 6LowPAN (IPv6 for constrained devies) * Thread (Mesh network layer) * UDP or CoAP (CoAP is like http for connectionless networks)

You need a bridge to connect CHIP to the internet (e.g. Apple Home). It was cool to route IP packets directly to lightbulbs from aws, but we don't bridge the networks in practice and all incoming/outgoing traffic goes through the bridge application.

Matter is the protocol running on top of IP, so it runs over Ethernet in the example (since the Pi doesn't speak 802.15.4)