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  • Publication
    Métadonnées seulement
    Construction universelle d’objets partagés sans connaissance des participants
    Une construction universelle est un algorithme permettant à un ensemble de processus concurrents d’accéder à un objet partagé en ayant l’illusion que celui-ci est disponible localement. blue Nous présentons un algorithme permettant la mise en œuvre d’une telle construction dans un système à mémoire partagée. Notre construction est sans verrou, et contrairement aux approches proposées précédemment, ne nécessite pas que les processus accédant à l’objet partagé soient connus. De plus, elle est adaptative : en notant n le nombre total de processus dans le système et k < n le nombre de processus qui utilisent l’objet partagé, tout processus effectue Θ(k) pas de calcul en l’absence de contention.
  • Publication
    Métadonnées seulement
    LayStream: composing standard gossip protocols for live video streaming
    (: IEEE, 2014-9-8)
    Matos, Miguel
    ;
    ; ; ;
    Oliveira, Rui
    Gossip-based live streaming is a popular topic, as attested by the vast literature on the subject. Despite the particular merits of each proposal, all need to implement and deal with common challenges such as membership management, topology construction and video packets dissemination. Well-principled gossip-based protocols have been proposed in the literature for each of these aspects. Our goal is to assess the feasibility of building a live streaming system, LAYSTREAM, as a composition of these existing protocols, to deploy the resulting system on real testbeds, and report on lessons learned in the process. Unlike previous evaluations conducted by simulations and considering each protocol independently, we use real deployments. We evaluate protocols both independently and as a layered composition, and unearth specific problems and challenges associated with deployment and composition. We discuss and present solutions for these, such as a novel topology construction mechanism able to cope with the specificities of a large-scale and delay-sensitive environment, but also with requirements from the upper layer. Our implementation and data are openly available to support experimental reproducibility.