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– DEEDS' Overlay network architecture, showing the tree node types linked by various kinds of transports.
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In this paper, we describe a case study of the design and development of a group-conferencing tool suite, built on top of an overlay network based event dissemination framework, which is extensible via quality of service template plug-ins. We explain, for each of the tools, how the framework built-in conveniences were explored to create simple but...
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Context 1
... event dissemination model summarized above is matched by a distributed architecture designed with large-scale and heterogeneity support in mind. A three-tier overlay network of nodes makes up the core of the event dissemination infrastructure, as shown in Figure 2. The first tier of this logical network is known as the backbone and its server nodes typically handle the more demanding routing operations. ...
Citations
... In this scenario, algorithms used by IP multicasting routing protocols [32] to build diffusion trees, rooted at a rendezvous node, can be used to build overlay diffusion trees. This method can be used independently of the overlay routing substrate be an unstructured mesh [21, 30] or a structured overlay [56, 53, 50]. For example, Hermes [49] uses the Pastry [53] structured overlay as routing substrate. ...
In content-based publish/subscribe systems, messages target a dynamic group of participants whose expressed interests match the contents of the messages. In this generalization of multicasting communication, also dubbed content-based networking, naming, binding and communication are intertwined in the same substrate. Optimal content-based routing uses dissemination trees dynamically pruned to only cover the matching subscribers. It is a complex problem that has motivated significant research efforts. This paper presents a compilation of the main algorithms for routing messages in distributed content-based publish-subscribe systems proposed and published in the last decade. Discussion is focused on the content-based routing problem in respect to optimality, complexity and applicability. Moreover, whenever it is appropriate, the algorithms covered are also matched to similar algorithms familiar to the networking community, setting this paper apart from other surveys on the broad topic of publish/subscribe systems.
... In order to improve P2P and ALM concepts, Quality of Service (QoS) aspects should be taken into account, which will be one of the goals of this thesis. Different approaches, such as QRON [107,105], mOverlay [185], HostCast [106] and many others [142,101,104,62,3,189] have been introduced to enable different kinds of QoS functionality in P2P/ALM networks. ...
... In [62] a case study of the design and development of a group-conferencing tool suite is described. This suite is built on top of a JAVA-based overlay network event dissemination framework named DEEDS. ...
... Dependente do contexto, ´ e habitual usar a designação multicasting quando se trata de garantias mais frágeis, ou comunicação em grupo, quando se pretende fornecer garantias mais rigorosas. Em qualquer dos casos, os algoritmos e protocolos utilizados envolvem sempre o conjunto dos participantes e apresentam, quando se pretende que se adaptemàadaptemà grande escala, amplas oportunidades de optimização, através de hierarquização, e da intervenção dos nós que realizam encaminhamento [14]. A mesma linha de questões pode, pelo menos parcialmente, ser levantada a propósito da segurança e da distribuição de chaves [18]. ...
Agosto de 2007 Resumo Este documento versa a problemática dos algoritmos distribuídos de encaminhamento para suporte de comunicação multi-ponto (1 para N, M para N e N para 1). Estes algoritmos estão na base dos protocolos de encaminhamento multi-ponto (multicasting) usados em redes locais e metropolitanas, em redes móveis ad hoc, assim como na Internet. Para além da apresentação dos algoritmos e das suas características, o texto analisa o estado da sua utilização concreta para disponibilizar IP Multicast. Tal análise parte da situação de impasse que se vive actualmente na disponibilização generalizada ao público deste serviço, para pôr em evidência as razões de fundo do problema. Tomando como ponto de partida esta situação, são introduzidos e analisados sistemas e algoritmos usados para disponibilizar comunicação multi-ponto a nível aplicação, através de redes lógicas (redes P2P, redes overlay, . . .). O texto termina tirando conclusões sobre as limitações destá ultima aproximação e põe em evidência a necessidade de repensar aspectos arquitecturais da Internet, especialmente ao nível de controlo de acessos e da relação entre o nível rede e os níveis transporte e aplicação. 1 1 Introdução Este documento versa a problemática dos algoritmos distribuídos de encaminhamento para su-porte de comunicação multi-ponto (1 para N, M para N e N para 1). Na sua essência, a comu-nicação multi-ponto consiste na possibilidade de enviar mensagens simultaneamente para vários destinatários, ou ao contrário, de várias fontes para u unico destinatário. Esta funcionalidade tem grande aplicabilidade: difusão multimédia, difusão de mensagens, documentos ou de eventos, colaboração multi-participante, replicação de serviços, pesquisa de recursos, aquisição de dados de várias fontes em telemetria e redes de sensores, ... Estas diferentes aplicações têm requisitos variados com implicações multi-facetadas. Ao nível da definição da semântica da comunicação (garantias de ordem e fiabilidade e suas vari-antes) a comunicação multi-pontó e tema de investigação activa há mais de 20 anos, com aplicação a sistemas confiáveis, baseados na comunicação em grupo [15,16]. Ao nível do transporte mais convencional, a problemática da variação entre os membros do grupo da capacidade, da latência e da taxa de perca de pacotes, justifica também muitos anos de investigação em protocolos de trans-porte para comunicação multi-ponto [25,17]. Ao nível da segurança tem sido necessário reinventar os protocolos de autenticação e de garantia de confidencialidade para contextos multi-participante [18].
Today, services and data are integrated in ever new constellations, requiring easy, flexible and scalable integration of autonomous, heterogeneous components into complex systems at any time. Event-based architectures inherently decouple system components, because event-based components are not designed to work with other components in traditional request/reply mode, but divide communication from computation through asynchronous communication mechanisms via a dedicated notification service. The authors provide an in-depth description of event-based systems. They cover the complete spectrum of topics, ranging from a treatment of local event matching and distributed event forwarding algorithms, through a practical discussion of software engineering issues raised by the event-based style, to a presentation of state-of-the-art research topics in event-based systems, such as composite event detection and security. The book gives researchers a comprehensive overview of the area and offers lots of ideas for future research. In addition, it shows the power of event-based architectures in modern system design, encouraging professionals to exploit this te.
This dissertation describes the design and evaluation of the Fast, Flexible Forwarding system (F3), a distributed system for disseminating information to networked subscribers. It examines existing subscription approaches, proposes F3 as an alternative to these approaches, and presents results from comparisons of F3 and other subscription approaches. Existing subscription approaches examined in the dissertation fall into three categories: unicast, single-identifier multicast, and content-based multicast systems. Careful examination of these approaches suggests that none is able to support complex subscription requests from large numbers of subscribers at high data rates. F3, the systems proposed as an alternative, shares many features with other multicast systems. Like many multicast systems, for example, F3 uses an overlay network of routers to distribute messages to subscribers. F3 differs from other systems, however, in its use of preprocessors to analyze messages before routing begins. Preprocessors carry out analyses of the relationships between subscription topics, and store the results in special content graph data-structures. Preprocessors share the results of their analyses by distributing content graphs to routers in the F3 network. Using content graphs, F3 routers can determine the relationships between subscriptions and notifications more efficiently than in previous approaches. Four studies compared performance of F3 and competing subscription systems. In the four studies, subscription systems handled such tasks as disseminating baseball scores, distributing traffic alerts, and disseminating generic subscriptions formatted as attribute-value pairs.
