The paper revisits the performance evaluation of caching in a Named Data Networking (NDN) router where the content store (CS) is supplemented by a pending interest table (PIT). The PIT aggregates requests for a given content that arrive within the download delay and thus brings an additional reduction in upstream bandwidth usage beyond that due to CS hits. We extend prior work on caching with non-zero download delay (non-ZDD) by proposing a novel mathematical framework that is more easily applicable to general traffic models and by considering alternative cache insertion policies. Specifically we evaluate the use of an LRU filter to improve CS hit rate performance in this non-ZDD context. We also consider the impact of time locality in demand due to finite content lifetimes. The models are used to quantify the impact of the PIT on upstream bandwidth reduction, demonstrating notably that this is significant only for relatively small content catalogues or high average request rate per content. We further explore how the effectiveness of the filter with finite content lifetimes depends on catalogue size and traffic intensity.

中文翻译：

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关于 PIT 在减少 NDN 路由器上行需求方面的有效性

本文重新审视了命名数据网络 (NDN) 路由器中缓存的性能评估，其中内容存储 (CS) 由未决兴趣表 (PIT) 补充。PIT 聚合对在下载延迟内到达的给定内容的请求，从而使上游带宽使用量额外减少，而不是由于 CS 命中。我们通过提出一种更容易适用于一般流量模型的新颖数学框架并考虑替代缓存插入策略，扩展了先前关于非零下载延迟（非 ZDD）缓存的工作。具体来说，我们评估了使用 LRU 过滤器来提高非 ZDD 上下文中的 CS 命中率性能。由于内容生命周期有限，我们还考虑了需求时间局部性的影响。这些模型用于量化 PIT 对上游带宽减少的影响，特别表明这仅对相对较小的内容目录或每个内容的高平均请求率具有重要意义。我们进一步探讨了具有有限内容生命周期的过滤器的有效性如何取决于目录大小和流量强度。