Address Resolution Protocol (ARP) is a protocol or technique in a local-area network(LAN). that relates a whole Internet Protocol (IP) address to a consistent physical machine address, also known as a media access control (MAC) address.
This mapping technique is crucial since the lengths of IP and MAC addresses differ, requiring a translation so that the machines may communicate with one another. IP version 4 is the most commonly used IP nowadays (IPv4). An IP address is 32 bits. In comparison, MAC addresses are 48 bits long. ARP translates a 32-bit address to a 48-bit address and the other way around.