CNS Core: Small: Designing Efficient Cloud Datacenter Network Fabrics

云数据中心网络的任务是在不断增加的终端主机之间提供连接，这些终端主机的链路速率每隔几年就会提高几个数量级。 网络运营商最理想的是一个单一的、全带宽的交换机，它可以以全速连接每个端点。 这样一个理想化的网络将使他们能够将工作和数据放在方便的地方，而不必担心带宽瓶颈，热点和其他网络引起的限制。 不幸的是，保持这种“大交换机”的错觉，一个完整的带宽单一的网络越来越成本高昂，可能很快就不可行。这个项目将探讨一种替代方法，构建数据中心网络结构的基础上，可证明的最佳拓扑结构，扩展图。 如果成功，该项目将产生比现有最先进方法更灵活，功能更强大，可扩展性更强的网络结构。 该项目将开发一系列基于扩展图的云数据中心网络拓扑，消除基于Clos的分层拓扑中固有的容量瓶颈，同时最大限度地减少间接路由导致的带宽税。 单个大型扩展器图网络拓扑可以由多个不相交的扩展器图构建;该项目将展示如何明智地放置租户，从而提供隔离和动态容量，同时最大限度地减少带宽税。 此外，通过采用可重新配置的网络组件（即，电路交换机），甚至可以在各种时间尺度上演进组成扩展图的集合，从而允许云数据中心运营商更好地适应其当前租户的需求。事实上，如果时间尺度足够小（例如，数百毫秒）的租户然后可以选择缓冲业务，直到特别有利的路径（集合）可用，进一步降低了总体带宽效率低下或“负担”。如果网络拓扑以快速的速率发展，则可以在每个分组的基础上选择是否（1）通过当前实例化的任何静态扩展器立即发送分组，对这一小部分业务产生适度的负担，或者（2）缓冲分组并等待直到建立到最终目的地的直接链路，消除对绝大多数字节的带宽税。该项目将通过结构化课程，密集的指导，和动手研究活动，通过参与NSF资助的加州大学圣地亚哥分校早期研究学者计划（ERSP）该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Cloud datacenter networks are tasked with providing connectivity between an ever-increasing number of end hosts whose link rates improve by orders of magnitude every few years. What network operators would ideally like is a single, full-bandwidth switch that could connect every endpoint at full rate. Such an idealized network would enable them to place jobs and data where it is convenient, without worrying about bandwidth bottlenecks, hotspots, and other network-induced limitations. Unfortunately, preserving this ``big-switch'' illusion of a single network with full bandwidth is increasingly cost prohibitive and likely soon infeasible.This project will explore an alternative method of constructing datacenter network fabrics based upon a provably optimal topological construct, an expander graph. If successful, the project will result in network fabrics that are more flexible, capable, and scalable than existing state-of-the-art approaches. This project will develop a family of cloud datacenter network topologies based on expander graphs that eliminate the capacity bottlenecks inherent in hierarchical Clos-based topologies while minimizing the bandwidth tax incurred due to indirect routing. A single, large expander-graph network topology can be constructed out of multiple, disjoint expander graphs; this project will show how judicious tenant placement can then provide both isolation and dynamic capacity while minimizing the bandwidth tax. Moreover, by employing reconfigurable network components (i.e., circuit switches), it is even possible to evolve the set of constituent expander graphs over various time scales, allowing cloud datacenter operators to better suit the needs of their current tenants. Indeed, if the timescales are sufficiently small (e.g., 100s of milliseconds) tenants may then choose to buffer traffic until a particularly favorable (set of) path(s) is available, further decreasing the overall bandwidth inefficiency or "tax". If the network topology evolves at a rapid rate, it is possible to choose, on a per-packet basis, whether to either (1) immediately send a packet over whatever static expander is currently instantiated, incurring a modest tax on this small fraction of traffic, or (2) buffer the packet and wait until a direct link is established to the ultimate destination, eliminating the bandwidth tax on the vast majority of bytes.This project will engage graduate and undergraduate students through structured courses, intense mentorship, and hands-on research activities through participation in the NSF-funded UC San Diego Early Research Scholars Program (ERSP).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.