(Xpress Transfer Protocol) A research transport protocol designed by Greg Chesson of SGI. Designed for high-speed networks, it provides services at layers 3 and 4 of the OSI model. XTP is flexible and can accommodate both real-time and non-real-time traffic by setting its own rate and flow control. It can also break data into multiple streams that are transmitted in parallel. ANSI's version of XTP is called "High Speed Transport Protocol" (HSTP).