There is MDNS for example. Also in terms of alternatives to BGP, you're still going to need to figure out routes. And / or, you going to have to detect loops. D

There is MDNS for example. Also in terms of alternatives to BGP, you're still going to need to figure out routes. And / or, you going to have to detect loops. Different "anycast" nodes could use something like this to detect each other's presence. You could use the (IP) TTL to limit how many hops a packet will traverse looking for a particular server (no similar concept at the MAC level AFAIK). I hope you have fun!