自适应一致性对分布式SDN应用的影响：一项实证研究
Impact of Adaptive Consistency on Distributed SDN Applications: An Empirical Study
摘要：
软件定义网络（SDN）中的控制平面的可扩展性通过决策逻辑的分散来实现，即，通过将控制器功能复制到物理上或虚拟上错位的控制器副本。集中式控制器状态的复制还能够通过负责管理底层SDN数据平面设备的主副本和备份副本来防止控制器故障。在本文中，我们调查部署的一致性模型的SDN控制平面的可扩展性和正确性度量的效果。特别是，我们比较强的和最终的一致性，并提出了一种新的自适应一致性方法的情况下。现有的控制器平台在其状态分布中依赖于强一致性机制或最终一致性机制。我们展示了如何自适应一致性模型提供的可扩展性方面的好处，总的请求处理吞吐量和响应时间，在强一致性模型。我们还概述了如何自适应一致性的方法可以提供正确性语义是无法实现的最终一致性范例在实践中。我们的方法的适应性提供了一个平衡和可调的权衡的可扩展性和正确性的SDN应用程序上实现的自适应框架。为了验证我们的假设，我们评估和比较不同的方法在一个模拟的测试床的负载均衡器控制器应用程序的一个例子。实验设置包括多达五个扩展OpenDaylight控制器实例和来自服务提供商和数据中心网络的两个网络拓扑。
英文摘要：
Scalability of the control plane in a software-defined network (SDN) is enabled by means of decentralization of the decision-making logic, i.e., by replication of controller functions to physically or virtually dislocated controller replicas. Replication of a centralized controller state also enables the protection against controller failures by means of primary and backup replicas responsible for managing the underlying SDN data plane devices. In this paper, we investigate the effect of the deployed consistency model on scalability and correctness metrics of the SDN control plane. In particular, we compare the strong and eventual consistency, and make a case for a novel adaptive consistency approach. The existing controller platforms rely on either strong or eventual consistency mechanisms in their state distribution. We show how an adaptive consistency model offers the scalability benefits in terms of the total request-handling throughput and response time, in contrast to the strong consistency model. We also outline how the adaptive consistency approach can provide for correctness semantics that are unachievable with the eventual consistency paradigm in practice. The adaptability of our approach provides a balanced and tunable tradeoff of scalability and correctness for the SDN application implemented on top of the adaptive framework. To validate our assumptions, we evaluate and compare the different approaches in an emulated testbed with an example of a load balancer controller application. The experimental setup comprises up to five extended OpenDaylight controller instances and two network topologies from the area of service provider and data center networks.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
