> Ironically, wireless networks are still very much like the original "you've got a piece of wire and everyone yells into it after listening for a short period of time" mechanism.

Maybe not that ironically since Ethernet derives from ALOHANet, the wireless network connecting Hawaiian schools. Early Ethernet was basically ALOHANet piped over a wire instead of radio waves just like cable tv for a while was just broadcast TV over wires instead of radio waves. https://en.wikipedia.org/wiki/ALOHAnet

L3 switches are absolutely a thing, they allow communication between different VLANs on the same hardware without needing to go through a router.

A layer 3 switch is just a switch and a router in the same chassis.

I have layer 3 switches doing eBGP.

We used to joke that Cisco would sell you either a switch that could route or a router that switches also.

Well, the "OSI" model where there's a little disassembly and assembly line in your box, where each layer gets taken off by one robot and the payload of that inside package gets handed off to another concern -- all lies.

The chips that do this (if they've got the features, anyhow) do L2, L3, L4, L5, etc all at the same time. So it's not an L2 switch and L3 router -- it's both at the same time, looking at the whole packet at once.

But -- there is no such thing as an ethernet "router" -- it's just a bridge with a forwarding table populated (usually) by listening for MAC addresses and updating forwarding tables. "flood and learn" There are even less ethernetty things out there that use the ethernet signaling but mechanically populate the forwarding tables of switches.

But a "thing that forwards between vlans" usually means "a thing that forwards packets from one L3 subnet to another."

You could probably make some insane custom switch that has routing rules for forwarding mac address packets from one vlan to another based on a bunch of zany rules, but such a cursed object would be hated universally by all who come after you.