ARP Reply from R1 to Hannah

Inside the data portion of the packet, the ARP reply contains the original IP address (8.1.1.250) and the corresponding MAC address (0200.3333.3333). Finally, Hannah knows the Ethernet MAC address that corresponds to the default gateway IP address.

Hannah puts the information in a place called the ARP cache, so that the next time she needs to send a packet to the default gateway, she does not need to send another ARP broadcast. An ARP cache is nothing more than a place in memory in an IP host where IP addresses and their corresponding MAC addresses are recorded.