Internet Protocol, DARPA Internet Program Protocol Specification.

The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks. Such a system has been called a catenet 1. The internet protocol provides for transmitting blocks of data called datagrams from sources to destinations, where sources and destinations are hosts identified by fixed length addresses. The internet protocol also provides for fragmentation and reassembly of long datagrams, if necessary, for transmission through small packet networks.