Fine-grained flow management is useful in many practical applications, e.g., resource allocation, anomaly detection and traffic engineering. However, it is difficult to provide fine-grained management for a large number of flows in SDNs due to switches’ limited flow table capacity. While using wildcard rules can reduce the number of flow entries needed, it cannot fully ensure fine-grained management for all the flows without degrading application performance. In this article, we design and implement hybrid rule placement for fine-grained flow management (to be referred to as HiFi here after). HiFi achieves fine-grained management with a minimal number of flow entries through taking a two-step approach: wildcard entry installment and application-specific exact-match entry installment. How to optimally install wildcard and exact-match flow entries, however, is intractable. Therefore, we design approximation algorithms with bounded factors to solve these problems. We consider how to achieve network-wide load balancing via fine-grained flow management as a case study. Both experiment on a testbed built with open virtual switches and extensive simulation show that HiFi can reduce the number of required flow entries by about 45-69 percent and reduce the control overhead by about 28-50 percent compared with the state-of-the-art approaches for achieving fine-grained flow management.

中文翻译：

---

通过 SDN 中的混合规则放置实现细粒度的流管理

细粒度的流管理在许多实际应用中都很有用，例如资源分配、异常检测和流量工程。然而，由于交换机的流表容量有限，难以对SDN中的大量流进行细粒度管理。虽然使用通配符规则可以减少所需的流条目数量，但它不能完全确保对所有流进行细粒度管理而不降低应用程序性能。在本文中，我们为细粒度流管理（以下简称 HiFi）设计并实现了混合规则放置。HiFi采用通配符入口安装和应用特定精确匹配入口安装两步法，以最少的流入口实现细粒度管理。如何以最佳方式安装通配符和精确匹配流条目，然而，是棘手的。因此，我们设计了具有有界因子的近似算法来解决这些问题。我们考虑如何通过细粒度流管理实现网络范围的负载平衡作为案例研究。在使用开放式虚拟交换机构建的测试台上进行的实验和广泛的模拟都表明，与当前的状态相比，HiFi 可以将所需的流条目数量减少约 45-69%，并将控制开销减少约 28-50%。实现细粒度流管理的艺术方法。