Address Resolution Protocol ARP
Most modern computers have an Ethernet interface with two distinct types of addresses: an Ethernet Address, and an IP Address. Ethernet addresses are always used when information is exchanged through an Ethernet interface, but IP addresses are not always used. The designers of the Internet developed clever ways to translate back and forth between Ethernet Addresses and IP addresses, and your computer's operating system uses these mechanisms all the time. Our movie entitled "Address Resolution Protocol ARP" explains how a computer that knows the IP address of a neighbor can translate that information into the associated IP address. A free, low-resolution version is available in several short segments commencing here, and you can purchase the high-resolution one (in any of our 5 standard video formats) here.