This paper introduces DISPERSE, a distributed scalable architecture for delivery of content and services that provides resilience against node failure through location-independent storage and replication of content. Current content delivery networks (CDNs) have, at least to some degree, a centralized structure thus susceptible to a single point of failure. DISPERSE addresses this limitation by implementing a fully de-centralized structure. DISPERSE is a two-layer architecture: the first layer (front-end layer) exposes services (e.g., Web, SFTP) to clients; the second layer (back-end layer) provides reliable distributed storage of content and application state. Content in DISPERSE’s back-end layer is stored and exchanged as Named Data Network (NDN) content objects. This allows DISPERSE to implement fine-grained, location-independent, fully decentralized content replication mechanisms. We validate the performance of DISPERSE under two node failure scenarios. In the first scenario, content can be stored in any DISPERSE node, and all nodes are equally likely to fail. In this scenario, we use non-linear optimization techniques to determine the optimal number of content copies under availability and latency constraints. In the second scenario, different nodes fail with different probabilities, and content is stored in nodes according to its value, node failure probability, and resource availability. This scenario is addressed as an instance of the minimum cost flow problem. Our results show that DISPERSE reduces the failure of content retrieval by five orders of magnitude compared to common CDN implementations, without significantly increasing content retrieval delay. Further, numerical results show that DISPERSE improves content availability by a factor of $1.3\times - 2.3\times $ when deploying the minimum cost flow algorithm.

中文翻译：

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DISPERSE：一种可抵御节点故障的内容复制的去中心化架构

本文介绍了 DISPERSE，这是一种用于交付内容和服务的分布式可扩展架构，它通过与位置无关的内容存储和复制提供针对节点故障的弹性。当前的内容交付网络 (CDN) 至少在某种程度上具有集中式结构，因此容易出现单点故障。DISPERSE 通过实施完全去中心化的结构解决了这一限制。DISPERSE 是一个两层架构：第一层（前端层）向客户端公开服务（例如，Web、SFTP）；第二层（后端层）提供内容和应用程序状态的可靠分布式存储。DISPERSE 后端层中的内容作为命名数据网络 (NDN) 内容对象进行存储和交换。这允许 DISPERSE 实现细粒度的、位置无关的、完全去中心化的内容复制机制。我们在两个节点故障场景下验证了 DISPERSE 的性能。在第一种情况下，内容可以存储在任何 DISPERSE 节点中，并且所有节点发生故障的可能性相同。在这种情况下，我们使用非线性优化技术来确定可用性和延迟约束下的最佳内容副本数量。在第二种场景中，不同的节点以不同的概率发生故障，内容根据其值、节点故障概率和资源可用性存储在节点中。这种情况作为最小成本流问题的一个实例来解决。我们的结果表明，与常见的 CDN 实现相比，DISPERSE 将内容检索的失败减少了五个数量级，而不会显着增加内容检索延迟。更多，