The IP address for a node is a logical address, independent of any particular hardware, network topology, or media type. The IP address is a 4-byte (32-bit) numeric value that identifies both a network and a local host or node (computer or other device) on that network. The 4-byte IP address is usually represented in dotted decimal notation. Each byte is represented by a decimal number, and periods separate the bytes, for example, 129.47.6.17.
A conflict arises with Ethernet networks, because IP uses a 32-bit address and Ethernet uses a 48-bit Ethernet address. To associate the IP address to a physical address on an Ethernet network, a mapping must occur between the two types. The Address Resolution Protocol (ARP) maps the IP address to the physical address. ARP mapping is limited to networks that support hardware broadcast.