The Address Resolution Protocol is a request and reply protocol that runs encapsulated by the line protocol. It is communicated within the boundaries of a single network, never routed across internetwork nodes. This property places ARP into the Link Layer of the Internet Protocol Suite, while in the Open Systems Interconnection (OSI) model, it is often described as residing between Layers 2 and 3, being encapsulated by Layer 2 protocols. However, ARP was not developed in the OSI framework.
Address translation or address resolution may refer to:
Address Resolution Protocol or ARP, a computer networking protocol used to find out the hardware address of a host (usually a MAC address), when only the network layer address is known
Reverse Address Resolution Protocol or RARP, a protocol used to find the network layer address of a host, based only on the hardware address. This protocol has been rendered obsolete by both BOOTP and DHCP
Domain name system or DNS, which is used to translate network addresses to human-recognizable domain names