Address Resolution Protocol

protocol which supplies addresses to workstations on a local area network

In computer networking, the Address Resolution Protocol (ARP) is the standard method for finding a host's hardware address when only its network layer address is known.ARP is not an IP-only or Ethernet-only protocol; it can be used to resolve many different network-layer protocol addresses to hardware addresses, although, due to the overwhelming prevalence of IPv4 and Ethernet, ARP is primarily used to translate IP addresses to Ethernet MAC addresses. It is also used for IP over other LAN technologies, such as Token Ring, FDDI, or IEEE 802.11, and for IP over ATM.
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A Transmission Control Protocol/Internet Protocol (TCP/IP) protocol that dynamically binds a Network-Layer IP address to a Data-Link-Layer physical hardware address, e.g., Ethernet address.

<networking, protocol> (ARP) A method for finding a host's Ethernet address from its Internet address. The sender broadcasts an ARP packet containing the Internet address of another host and waits for it (or some other host) to send back its Ethernet address. Each host maintains a cache of address translations to reduce delay and loading. ARP allows the Internet address to be independent of the Ethernet address but it only works if all hosts support it.
ARP is defined in RFC 826.
The alternative for hosts that do not do ARP is constant mapping.
See also proxy ARP, reverse ARP.
(1995-03-20)