[vegardx]

In AWS you don't even do neighbour discovery through ARP. Or that's a lie, you do, you get a arp reply, but it's not from any of your devices on the network. And traffic is authenticated and authorized at both the source and destination, so you can't do fun things like manipulating arp tables. You get a lot of nice features when you have a fully software defined network, but it comes with a couple of caveats, like you mentioned here. I doubt we'll ever see "real multicast support" in the sense that network engineers are used to.