397 research outputs found

    Internet Protocol (IP) Multicast: Final Report

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    Report presents the results of the Institute for Simulation and Training\u27s implementation and integration of new protocols into the Testbed for Research in Distributed Interactive Simulation (TRDIS) testbed, especially the Internet Protocol (IP) Multicast (IPmc) and Internet Group Management Protocol network protocols, into a simulation application

    The Timed Concurrent Constraint language in practice

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    We propose the tccp language for the specification and verification of security protocols. We study the relation between tccp and utcc by presenting a transformation from utcc into tccp that formally states the relation between the two languages. Finally, we present an interpreter for tccp implemented in Maude.Lescaylle Daudinot, A. (2009). The Timed Concurrent Constraint language in practice. http://hdl.handle.net/10251/14517Archivo delegad

    Regular Topologies for Gigabit Wide-Area Networks: Congestion Avoidance Testbed Experiments

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    This document is Volume 3 of the final technical report on the work performed by SRI International (SRI) on SRI Project 8600. The document includes source listings for all software developed by SRI under this effort. Since some of our work involved the use of ST-II and the Sun Microsystems, Inc. (Sun) High-Speed Serial Interface (HSI/S) driver, we have included some of the source developed by LBL and BBN as well. In most cases, our decision to include source developed by other contractors depended on whether it was necessary to modify the original code. If we have modified the software in any way, it is included in this document. In the case of the Traffic Generator (TG), however, we have included all the ST-II software, even though BBN performed the integration, because the ST-II software is part of the standard TG release. It is important to note that all the code developed by other contractors is in the public domain, so that all software developed under this effort can be re-created from the source included here

    New perspectives on the IPv6 transition

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    Despite it being more than a decade old, and nearly two decades since the problems with IPv4 were first identified, IPv6 still has not diffused significantly through the Internet. Policies advocating market forces to promote IPv6 diffusion are widespread, and thus this paper examines IPv6 adoption from the perspectives of Hotelling's aconomics of exhaustible resources and the economics of permit markets, concluding in both cases that significant IPv6 diffusion will not occur until after the IPv4 address space is exhausted. This outcome is not desirable, and therefore new policy alternatives must be debated

    Um modelo de qualidade de serviço baseado em ATM para a plataforma multiware

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    Orientador: Edmundo Roberto Mauro MadeiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As recentes mudanças no paradigma de computação em rede, marcadas pelo surgimento de aplicações distribuídas complexas e o uso de multimídia em larga escala, representam um novo desafio com relação aos protocolos e plataformas distribuídas em uso atualmente. Nesse contexto, os aspectos não-funcionais dos sistemas, que descrevem o desempenho das aplicações, tornam-se cada vez mais importantes. Esses aspectos, agrupados sob o nome "Qualidade de Serviço" , são endereçados nesta dissertação, sob o contexto de plataformas distribuídas e das redes ATM. Esta dissertação propõe um modelo de Qualidade de Serviço de múltiplos níveis para.a plataforma Multiware, englobando a especificação, negociação e controle da Qualidade de Serviço. O modelo proposto é baseado em redes ATM, no modelo RM-ODP e na arquitetura CORBA. Visando a validação do modelo, foi desenvolvido um protótipo que implementa protocolos nos níveis de rede, de transporte e de distribuição.Abstract: The recent changes occurred on the network computing paradigm, sealed by the appearance of complex distributed applications and the broad use of multimedia, represents a new challenge to the protocols and distributed platforms in use today. In this context, non-functional aspects of the systems, representing the performance of the applications, became very important. Those aspects, under que name "Quality of Service" , are addressed here, in the context of distributed platforms and ATM networks. This work proposes a Quality of Service model with multiple levels to the Multiware platform, covering specification, negotiation and control of the quality of service. This model is based on ATM networks, RM-ODP model and CORBA architecture. To validate the model, a prototype has been developed, that implements protocols on network, transport and distribution levels.MestradoMestre em Ciência da Computaçã

    Transmission d'événements musicaux en temps réel sur Internet

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    Nous présentons un nouveau protocole s'appuyant sur UDP, permettant de transmettre des événements datés en temps réel et fournissant au récepteur, les moyens d'une restitution temporelle correcte. Ce protocole inclus des mécanismes permettant de compenser la latence du réseau et d'optimiser l'utilisation de la bande passante. Il prend également en compte les dérives d'horloges des différentes machines impliquées dans une transmission. Il est particulièrement adapté à la transmission d'événements musicaux tels que les messages MIDI

    Advanced Signaling Support for IP-based Networks

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    This work develops a set of advanced signaling concepts for IP-based networks. It proposes a design for secure and authentic signaling and provides QoS signaling support for mobile users. Furthermore, this work develops methods which allow for scalable QoS signaling by realizing QoS-based group communication mechanisms and through aggregation of resource reservations

    A QoS-enabled resource management scheme for F-HMIPv6 micro mobility approach

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    In the near future, wireless networks will certainly run real-time applications with special Quality of Service (QoS) requirements. In this context micro mobility management schemes such as Fast Handovers over Hierarchical Mobile IPv6 (F-HMIPv6) will be a useful tool in reducing Mobile IPv6 (MIPv6) handover disruption and thereby to improve delay and losses. However, F-HMIPv6 alone does not support QoS requirements for real-time applications. Therefore, in order to accomplish this goal, a novel resource management scheme for the Differentiated Services (DiffServ) QoS model is proposed to be used as an add-on to F-HMIPv6. The new resource management scheme combines the F-HMIPv6 functionalities with the DiffServ QoS model and with network congestion control and dynamic reallocation mechanisms in order to accommodate different QoS traffic requirements. This new scheme based on a Measurement-Based Admission Control (MBAC) algorithm is effective, simple, scalable and avoids the well known traditional resource reservation issues such as state maintenance, signaling overhead and processing load. By means of the admission evaluation of new flows and handover flows, it is able to provide the desired QoS requirements for new flows while preserving the QoS of existing ones. The evaluated results show that all QoS metrics analyzed were significantly improved with the new architecture indicating that it is able to provide a highly predictive QoS support to F-HMIPv6

    Entwurfsbegleitende Leistungsanalyse für SDL-basiertes Design multimedialer Internet-Transportsysteme

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    Neben der funktionalen Korrektheit von komplexen Kommunikationssystemen spielt eine ausreichende Performance dieser Systeme eine immer wichtigere Rolle. Dabei ist es notwendig, Performance-Aspekte bereits in frühen Entwurfsphasen und nicht erst nach der Implementierung der Systeme zu berücksichtigen. Die vorliegende Arbeit präsentiert eine Methodik zur entwurfsbegleitenden, modellgestützten Leistungsanalyse von Kommunikationsprotokollen, die mit Hilfe der Sprache SDL formal spezifiziert wurden. Die vorgestellte Methodik verwendet dazu Beschreibungsmechanismen, Verfahren und Werkzeuge, die bereits im Entwurfsprozeß dieser Systeme verwendet werden. Für die wichtigsten Implementierungsansätze von Kommunikationsprotokollen werden Performance-Bausteine vorgestellt und deren Verwendung erläutert. Die Tragfähigkeit der entwickelten Methodik wird durch eine große Fallstudie im Kontext von Reservierungsprotokollen zur Unterstützung von Multimedia-Anwendungen im Internet demonstriert. Dabei werden nicht nur die informellen Angaben der vorhandenen RFCs in formale SDL-Beschreibungen umgesetzt, sondern auch als existent vorausgesetzte Ressource-Management-Funktionen entwickelt und analysiert. Die vorliegende Arbeit schließt so die bisher bestehende Lücke im SDL-basierten Entwurfsprozeß verteilter reaktiver Systeme und ermöglicht die modellgestützte Betrachtung von Performance-Aspekten in den frühen Phasen des Entwurfsprozesses
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