Internet Datagram Protocol Specification. Version 4

The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks. Such a system has been called a catenet. 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. The internet protocol is specifically limited in scope to provide the functions necessary to deliver a package of bits an internet datagram from a source to a destination over an interconnected system of networks. There are no mechanisms to promote data reliability, flow control, sequencing, or other services commonly found in host-to-host protocols. This protocol is called on by host-to-host protocols in an internet environment. This protocol calls on local network protocols to carry the internet packet to the next gateway or destination host.