Address Resolution Protocol (ARP)

Address Resolution Protocol (ARP)

Three types of address information are used on TCP/IP internetworks:

Physical addresses. Used by the Data Link and Physical layers.
IP addresses. Provide logical network and host IDs. IP addresses consist of four numbers typically expressed in dotted-decimal form. An example of an IP address is 134.135.100.13.
Logical node names. Identify specific hosts with alphanumeric identifiers, which are easier for users to recall than the numeric IP addresses. An example of a logical node name is MYHOST.COM.

Given a logical node name, the Address Resolution Protocol (ARP) can determine the IP address associated with that name. ARP maintains tables of address resolution data and can broadcast packets to discover addresses on the internetwork. The IP addresses discovered by ARP can be provided to Data Link layer protocols.