The growth of cloud-based services is mainly supported by the core networking infrastructures of large-scale data centers, while the scalability of these services is influenced by the performance and dependability characteristics of data centers. Hence, the data center network must be agile and reconfigurable in order to respond quickly to the ever-changing application demands and service requirements. The network must also be able to interconnect the big number of nodes, and provide an efficient and fault-tolerant routing service to upper-layer applications. In response to these challenges, the research community began exploring novel interconnect topologies, namely: Flecube, DCell, Ficonn, HyperFlaNet and BCube. However, these topologies either scale too fast (grows exponentially in size), or too slow, and therefore suffer from performance bottlenecks. In this paper, we propose a novel data center topology called LaScaDa (Layered Scalable Data Center) as a new solution for building scalable and cost-effective data center networking infrastructures. The proposed topology organizes nodes in clusters of similar structure, then interconnect these clusters in a well-crafted pattern and system of coordinates for nodes to reduce the number of redundant connections between clusters, while maximizing connectivity. LaScaDa forwards packets between nodes using a new hierarchical row-based routing algorithm. The algorithm constructs the route to the source based on the modular difference between the source and destination coordinates. Furthermore, the proposed topology interconnects a large number of nodes using a small node degree. This strategy increases the number of directly connected clusters and avoids redundant connections. As a result, we get a good quality of nodes in terms of average path length (APL), bisection bandwidth, and aggregated bottleneck throughput. Experimental results show that LaScaDa has better performance than DCell, BCube, and HyperBcube in terms of scalability, while providing a good quality of service.

中文翻译：

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LaScaDa：数据中心网络的新型可扩展拓扑

大型数据中心的核心网络基础架构主要支持基于云的服务的增长，而这些服务的可伸缩性则受数据中心的性能和可靠性特征影响。因此，数据中心网络必须灵活且可重新配置，以便快速响应不断变化的应用程序需求和服务需求。网络还必须能够互连大量节点，并为上层应用程序提供高效且容错的路由服务。为应对这些挑战，研究界开始探索新颖的互连拓扑，即：Flecube，DCell，Ficonn，HyperFlaNet和BCube。但是，这些拓扑的扩展速度太快（规模增长成指数增长），或者速度太慢，因此存在性能瓶颈。在本文中，我们提出了一种称为LaScaDa（分层可扩展数据中心）的新型数据中心拓扑，作为构建可扩展且具有成本效益的数据中心网络基础结构的新解决方案。拟议的拓扑将节点组织在结构相似的群集中，然后以精心设计的模式和节点的坐标系统将这些群集互连，以减少群集之间的冗余连接数，同时最大程度地提高连接性。LaScaDa使用新的基于行的分层路由算法在节点之间转发数据包。该算法根据源坐标和目标坐标之间的模数差构造到源的路线。此外，所提出的拓扑使用较小的节点度来互连大量节点。此策略增加了直接连接的群集的数量，并避免了冗余连接。结果，就平均路径长度（APL），二等分带宽和聚合瓶颈吞吐量而言，我们获得了良好的节点质量。实验结果表明，LaScaDa在可伸缩性方面比DCell，BCube和HyperBcube具有更好的性能，同时提供了良好的服务质量。