We design and deploy in production the first flat datacenter networks. Our design, called RNG, is based on quasi-random graphs. While the cost and fault-tolerance benefits of such topologies have been long known, their practical realization has been hampered by a lack of scalable routing and cabling approaches. RNG has a new distributed routing protocol that exploits the properties of random graphs to find a large number of edge disjoint paths between pairs of endpoints. It uses a novel passive optical device that internally shuffles cables, which makes its cabling complexity similar to that of fat trees. We show that RNG matches or exceeds the performance of fat trees for a range of traffic patterns, despite being up to 45% cheaper. RNG is now the default datacenter network for most workloads at Amazon.

翻译：我们设计并在生产环境中部署了首个扁平数据中心网络。该设计名为RNG，基于准随机图结构。尽管此类拓扑在成本与容错性方面的优势早已为学界所知，但由于缺乏可扩展的路由与布线方案，其实际落地始终受阻。RNG采用新型分布式路由协议，通过利用随机图的特性，在端点对之间发现大量边不相交路径。该架构使用了一种创新的无源光学器件对线缆进行内部引接，使其布线复杂度与胖树结构相当。研究表明，在多种流量模式下，RNG的性能可媲美甚至超越胖树结构，同时成本降低高达45%。目前，RNG已成为亚马逊多数工作负载的默认数据中心网络。