Forschungs- und Arbeitsgebiete des Instituts für Telematik

Dieser Interne Bericht gibt einen Ueberblick ueber aktuelle Forschungsarbeiten des Instituts fuer Telematik der Universitaet Karlsruhe in den Bereichen Hochleistungskommunikation, verteilte Systeme, Cooperation&Management und Telekooperation. Er ist in zwei Teile gegliedert. Der erste beschreibt die persoenlichen Interessensgebiete der wissenschaftlichen Mitarbeiter. Danach folgt eine Darstellung der Kooperationsprojekte des Instituts. Im Anhang finden sich die referenzierten Literaturstellen sowie aktuelle Eigenveroeffentlichungen der Mitarbeiter des Instituts. Der Bericht entstand im Rahmen der Klausurtagung des Instituts in Rothenburg ob der Tauber im Oktober 1996

Fundamentos informáticos

Fundamentos Informáticos es el sucesor de Apuntes de Informática, que surgió en el 95 fruto de la colaboración de una serie de profesores que impartíamos asignaturas de introducción a la informática en los Planes de Estudios de diversas Escuelas Técnicas y Facultades de la Universidad de Cádiz. Surgió ante la necesidad de crear unos apuntes para impartir la teoría de nuestras asignaturas, ya que, aunque la bibliografía en lo referente a temas de introducción a la Informática es muy amplia, no existía ningún libro que se adaptara plenamente a nuestras necesidades comunes. En Fundamentos Informáticos pretendemos tocar todos los aspectos básicos de la informática (el ordenador, los periféricos, representación de la información dentro del ordenador, algoritmos, programas, etc.). En el libro se ofrece más información de la que se puede exponer en un curso académico, sin embargo, esto no es un error cometido por nosotros, sino que es intencionado. Al ofrecer toda esa información, el profesorado que use este libro para impartir su asignatura, podrá seleccionar y navegar entre el mar de información que se le ofrece. Y el alumnado podrá utilizar este libro tanto de libro de texto como de consulta

The QuickRing Network

QuickRing 1 is a new low-cost high-speed communication network that provides a point-to-point bandwidth of up to 180 MBytes/s. We describe some of the features of the QuickRing architecture and protocol including the QuickRing controller, the data formats, the reservation protocol, and the routing mechanism. We then investigate the problem of determining the topology of a QuickRing network and present an algorithm for solving this problem using the ping-echo probing mechanism and the WhoRU-IAm node identification mechanism. Finally, we present performance results based on a simulation of QuickRing. 1 Introduction New technologies are providing high-speed communication networks to support a wide variety of computers and applications. The world is moving from Mbits/s with the Ethernet and FDDI [9] to Gbits/s with SCI [6], the Gigabit testbeds [5], and QuickRing [10]. The rate of errors in data transmission has fallen from 10 \Gamma6 to 10 \Gamma14 [8]. Packet loss is primarily du..

A Hardware Architecture for Gigabit Multicasting

The ultra-high data rate of modern communication media has challenged network designers to migrate communication protocol functions, traditionally implemented in software, to hardware. At the same time, new quality of service requirements from the higher-level network applications have complicated the functions of communication protocols. QuickRing is a high-speed slotted-ring network that consists of a single ring or multiple rings interconnected by bridges. The QuickRing multicast protocol provides an aggregate totally ordered delivery throughput of 1.3 Gbit/s and a latency of 5 ¯s under low load. The Gbit/s transmission rate, and the short processing time of a few tens of nano-seconds for each arriving symbol, mandates hardware implementation of the protocol. We present a hardware architecture for the protocol chip, evaluate the complexity and feasibility of the design, and discuss various design trade-off issues. To our knowledge, this is the first attempt to support totally ordere..

Flow Control Techniques for Multicasting in Gigabit Networks

Communication protocol designers are facing new challenges due to the development of high-speed networks and to the increasing demands of network applications. Gigabit networks pose a challenge to flow control techniques developed for traditional acknowledgment-based, and typically packet-switched, lower-speed networks. Network applications such as distributed databases, groupware and distributed multimedia, all of which require multicasting, have rendered insufficient existing point-to-point flow control methodologies. We examine the problem of flowcontrol for multicasting in gigabit networks. Instead of feedback or rate-adaptation techniques, we employ more active flow control mechanisms that use traffic information in protocol control frames. These techniques are very effective for the totally ordered multicast protocol we have developed for the QuickRing gigabit local-area network

Gigabit Network Multicast Protocols

This Ph.D. dissertation investigates protocols for a gigabit-per-second local-area network (LAN) as the successor to the first generation of 10 Mbit/s Ethernet and Token Ring LANs, and the second and current generation of 100 Mbit/s Fast Ethernet, FDDI, DQDB-MANs and 155 Mbit/s ATM networks. The communication medium of gigabit networks has the characteristics of an ultra-high data rate and an extremely low error rate. The design of the medium access control (MAC) mechanisms for the QuickRing gigabit LAN of this work not only exploits these characteristics to achieve high throughput and low latency, but also provides integrated support for the increasingly higher quality of service (QoS) demanded by the network applications. In the proposed MAC scheme, the fundmental communication mode is one-to-many or many-to-many multicast, which supports group communication as well as point-to-point unicast and broadcast. Based on this, a suite of MAC protocols has been developed to provide integrat..