Definition: IP is the primary network protocol used on the Internet, developed in the 1970s. On the Internet and many other networks, IP is often used together with the Transport Control Protocol (TCP) and referred to interchangeably as TCP/IP.
IP supports unique addressing for computers on a network. Most networks use the IP version 4 (IPv4) standard that features IP addresses four bytes (32 bits) in length. The newer IP version 6 (IPv6) standard features addresses 16 bytes (128 bits) in length. Data on an IP network is organized into packets. Each IP packet includes both a header (that specifies source, destination, and other information about the data) and the message data itself.