Definition: IP is probably the world's single most popular network protocol. Data travels over an IP-based network in the form of packets; each IP packet includes both a header (that specifies source, destination, and other information about the data) and the message data itself.
IP supports the notion of unique addressing for computers on a network. Current IP (IPv4) addresses contain four bytes (32 bits) that is sufficient to address most computers on the Internet.
IP supports protocol layering as defined in the OSI reference model. Popular higher-level protocols like HTTP, TCP, and UDP are built directly on top of IP. Likewise, IP can travel over several different lower-level data link interfaces like Ethernet and ATM. IP originated with UNIX® networking in the 1970s.
