The Xpress Transfer Protocol (XTP): A tutorial (expanded version)

The Xpress Transfer Protocol (XTP) is a reliable, real-time, light weight transfer layer protocol. Current transport layer protocols such as DoD's Transmission Control Protocol (TCP) and ISO's Transport Protocol (TP) were not designed for the next generation of high speed, interconnected reliable networks such as fiber distributed data interface (FDDI) and the gigabit/second wide area networks. Unlike all previous transport layer protocols, XTP is being designed to be implemented in hardware as a VLSI chip set. By streamlining the protocol, combining the transport and network layers and utilizing the increased speed and parallelization possible with a VLSI implementation, XTP will be able to provide the end-to-end data transmission rates demanded in high speed networks without compromising reliability and functionality. This paper describes the operation of the XTP protocol and in particular, its error, flow and rate control; inter-networking addressing mechanisms; and multicast support features, as defined in the XTP Protocol Definition Revision 3.4

The Xpress Transfer Protocol (XTP): A tutorial (short version)

The Xpress Transfer Protocol (XTP) is a reliable, light weight transfer layer protocol. Current transport layer protocols such as DoD's Transmission Control Protocol (TCP) and ISO's Transport Protocol (TP) were not designed for the next generation of high speed, interconnected reliable networks such as fiber distributed data interface (FDDI) and the gigabit/second wide area networks. Unlike all previous transport layer protocols, XTP is being designed to be implemented in hardware as a VLSI chip set. By streamlining the protocol, combining the transport and network layers, and utilizing the increased speed and parallelization possible with a VLSI implementation, XTP will be able to provide the end-to-end data transmission rates demanded in the high speed networks without compromising reliability and functionality. This tutorial briefly describes the operation of the XTP protocol and in particular, its error, flow and rate control; inter-networking addressing mechanisms; and multicast support features, as defined in the XTP Protocol Definition Revision 3.4

The multidriver: A reliable multicast service using the Xpress Transfer Protocol

A reliable multicast facility extends traditional point-to-point virtual circuit reliability to one-to-many communication. Such services can provide more efficient use of network resources, a powerful distributed name binding capability, and reduced latency in multidestination message delivery. These benefits will be especially valuable in real-time environments where reliable multicast can enable new applications and increase the availability and the reliability of data and services. We present a unique multicast service that exploits features in the next-generation, real-time transfer layer protocol, the Xpress Transfer Protocol (XTP). In its reliable mode, the service offers error, flow, and rate-controlled multidestination delivery of arbitrary-sized messages, with provision for the coordination of reliable reverse channels. Performance measurements on a single-segment Proteon ProNET-4 4 Mbps 802.5 token ring with heterogeneous nodes are discussed

XTP for the NASA space station

The NASA Space Station is a truly international effort; therefore, its communications systems must conform to established international standards. Thus, NASA is requiring that each network-interface unit implement a full suite of ISO protocols. However, NASA is understandably concerned that a full ISO stack will not deliver performance consistent with the real-time demands of Space Station control systems. Therefore, as a research project, the suitability of the Xpress transfer protocol (XTP) is investigated along side a full ISO stack. The initial plans for implementing XTP and comparing its performance to ISO TP4 are described

Performance study of the Xpress Transfer Protocol

This major report presents a study of the performance of the Kernel Reference Model (KRM) version 1.7, implementation of the Xpress Transfer Protocol (XTP) version 3.6. XTP is a "new generation" protocol, combining the network and transport layers. It is designed to respond to present and future computer applications, and to take advantage of the hardware possibilities. The performance measurements include unicast throughput and delay in an Ethernet network, in two different hardware configurations, one based on Sun-3 workstations, and the other one on Sun-4 workstations. The performance of the KRM is compared with that of other protocols such as the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP), all in the same environment and under the same condition

Evaluating error recovery mechanisms in the Xpress Transfer Protocol

Uses a real time environment to verify the error recovery mechanism of the Xpress Transfer Protocol (XTP) version 3.6, which has been specified in the Estelle specification language. Builds two modules to interact with the XTP Estelle specification module

Issues in designing transport layer multicast facilities

Multicasting denotes a facility in a communications system for providing efficient delivery from a message's source to some well-defined set of locations using a single logical address. While modem network hardware supports multidestination delivery, first generation Transport Layer protocols (e.g., the DoD Transmission Control Protocol (TCP) (15) and ISO TP-4 (41)) did not anticipate the changes over the past decade in underlying network hardware, transmission speeds, and communication patterns that have enabled and driven the interest in reliable multicast. Much recent research has focused on integrating the underlying hardware multicast capability with the reliable services of Transport Layer protocols. Here, we explore the communication issues surrounding the design of such a reliable multicast mechanism. Approaches and solutions from the literature are discussed, and four experimental Transport Layer protocols that incorporate reliable multicast are examined

Voice and video transmission using XTP and FDDI

The use of Xpress Transfer Protocol (XTP) and Fiber Distributed Data Interface (FDDI) provides a high speed and high performance network solution to multimedia transmission that requires high bandwidth. FDDI is an ANSI and ISO standard for a MAC and physical layer protocol that provides a signaling rate of 100 Mbits/sec and fault tolerance. XTP is a transport and network layer protocol designed for high performance and efficiency and is the heart of the SAFENET Lightweight Suite for systems that require performance or realtime communications. The testbed consists of several commercially available Intel based i486 PC's containing off-the-shelf FDDI cards, audio analog-digital converter cards, video interface cards, and XTP software. Unicast, multicast, and duplex audio transmission experiments have been performed using XTP software. Unicast and multicast video transmission is in progress. Several potential commercial applications are described