> It doesn't matter which subnet the next hop's IP is in, as the routing table isn't consulted for it anyway - it's only used in ARP) You can only ARP for host

> It doesn't matter which subnet the next hop's IP is in, as the routing table isn't consulted for it anyway - it's only used in ARP) You can only ARP for hosts on the same subnet as you, terrible hacks excluded. > This leaves the question, why the indirection and why the mucking around with ARP and IPs that are never used as the destination to anything? Because it was designed in layers so that different layers could be replaced. We didn't know we'd end up with mostly only IP and Ethernet in LANs back then. > Couldn't you simply put the next hop's MAC address (instead of IP address) into the routing table and be able to route packets just as well, with a lot less complexity? It could have been done in any number of ways. It's not that much complexity through and it would bake Ethernet MACs into everything IP, even in the cases where it's not needed.