 So, before we communicate on a network, we must resolve the IP address into a MAC address. And for that, we use what's called address resolution protocol or ARP for short. What will happen is the source computer or the source device will send out an ARP message. And that message may say, who has 192.168.0.1, please tell 192.168.0.2. This message happens to be what's called a broadcast. And a broadcast message is a message that is received by all computers on a network. All devices on a network receive this broadcast message. So every computer will look at their IP address and say, oh, do I have 192.168.0.1? Is that me? And if it's not, then all of the rest of the computers that are not 192.168.0.1 will discard that frame, discard this ARP message, won't even reply to it, just drop it. But the one computer that does have 192.168.0.1 will say, oh, hey, that's me. And it will construct what's called an ARP reply. And in the ARP reply, it says, I am 192.168.0.1, and my MAC address is D8, D1, CB, etc. This way, the source computer can construct an Ethernet frame with a source MAC address and a destination MAC address, which is what's required for communicating on local area networks.