ARP, Address Resolution Protocol

Unlike IP-only and Ethernet-only protocol, ARP can be used to resolve several addresses found on hardware. Due to the prevalence of Ethernet and IPv4 connections, address resolution protocol is mostly used to convert or translate IP addresses to MAC Ethernet addresses. It can also be used for an IP over LAN technologies such as Token Ring. ARP is typically used in four scenarios: 1. When a hosts wants to send a packet of data to another host on the same network. 2. When hosts on different networks need to use routers in order to reach one another 3. When a hosts needs to forward a packet to another host from router to router. 4. When a host needs a router to forward a packet to a host on the same network. In a TCP/IP network, ARP may be used in a local broadcast domain. This is done to determine the hardware address of another computer. When a broadcast packet containing that computer’s IP address has been distributed, the packet is recognized and responds to the request with it’s own packet that reveals an address to the original computer.