< protocol > (UDP) Internet standard network layer , transport layer and session layer protocols which provide simple but unreliable datagram services. UDP is defined in STD 6 , RFC 768 . It adds a checksum and additional process-to-process addressing information [to what?]. UDP is a connectionless protocol which, like TCP , is layered on top of IP .
UDP neither guarantees delivery nor does it require a connection. As a result it is lightweight and efficient, but all error processing and retransmission must be taken care of by the application program .
Unix manual page : udp(4).
[Postel, Jon, User Datagram Protocol, RFC 768, Network Information Center, SRI International, Menlo Park, Calif., August 1980].
(1998-02-11)