This is more of a question asked out of curiosity than for practical reasons, but it's bugging me, because it might point to a lack of understanding elsewhere. Back when classful IP addresses were used, how were IP addresses translated to MAC addresses in class B and class A networks?
I can't imagine ARP being a good idea, since that broadcasts to every host on the network. Was that just not a problem because no-one actually used more than a fraction of their address space?
Thanks for taking the time to look at this.