well it wouldn't be the router searching the ARP table. The sending client would do the lookup in its own ARP table. If it didn't have an address for x.x.1.4, it would do an ARP broadcast to get it. I don't think the router has a role in this situation. Why? because if the default route is 192.168.1.1 then it is probably already on that subnet. The client is going to realize the destination is on the same subnet using the subnet mask. If the router had an integrated switch, the switch would be involved in forwarding the frame. Anyways my $0.02