The Free On-line Dictionary of Computing (30 December 2018):

Xpress Transport Protocol

    (XTP) A transport layer protocol
   for high-speed networks promoted by the XTP Forum.  XTP
   provides protocol options for error control, flow control,
   and rate control.  Instead of separate protocols for each type
   of communication, XTP controls packet exchange patterns to
   produce different models, e.g. reliable datagrams,
   transactions, unreliable streams, and reliable multicast
   connections.

   XTP Home (http://ca.sandia.gov/xtp/).

   Contrast with Transmission Control Protocol.  XTP does not
   employ congestion avoidance algorithms.

   (2003-03-22)