Could someone help clarify how a host lets say "A" would communicate with host "B" on the same subnet, but has to pass through hubs and switches and doesn't know where "B" is. In terms of ARP, since only hubs and switches are involved would only be interested in MAC addresses, right? In this scenario no routers are involved.
Second scenario would be the same, except, now lets add that router, and connect multiple subnets. now host "A" wants to communicate with host "C" on a separate subnet, through hubs, switches and a router.
I'm assuming layers 1 2 and 3 are involved, ARP, IP and MAC addresses.