Toward Adaptive and Scalable OpenFlow-SDN Flow Control: A Survey

TLDR

Software‑defined networking centralizes control to simplify management and improve resource utilization, yet this separation creates scalability and performance challenges in large‑scale, dynamic networks. This survey reviews techniques that reduce control‑to‑data plane communication and controller consistency traffic to boost OpenFlow‑SDN scalability, and identifies future challenges for adaptive, scalable flow control. The authors examine four key areas—centralized visibility, link‑state discovery, flow‑rule placement, and controller load balancing—to evaluate existing solutions and their limitations. The study provides an updated, detailed assessment of current approaches and highlights their strengths and weaknesses in enhancing OpenFlow‑SDN scalability and performance.

Abstract

Software-defined networking (SDN) is an emerging network architecture that promises to simplify network management, improve network resource utilization, and boost evolution and innovation in traditional networks. The SDN allows the abstraction and centralized management of the lower-level network functionalities by decoupling the network logic from the data forwarding devices into the logically centralized distributed controllers. However, this separation introduces new scalability and performance challenges in large-scale networks of dynamic traffic and topology conditions. Many research studies have represented that centralization and maintaining the global network visibility over the distributed SDN controller introduce scalability concern. This paper surveys the state-of-the-art proposed techniques toward minimizing the control to data planes communication overhead and controllers' consistency traffic to enhance the OpenFlow-SDN scalability in the context of logically centralized distributed SDN control plane architecture. The survey mainly focuses on four issues, including logically centralized visibility, link-state discovery, flow rules placement, and controllers' load balancing. In addition, this paper discusses each issue and presents an updated and detailed study of existing solutions and limitations in enhancing the OpenFlow-SDN scalability and performance. Moreover, it outlines the potential challenges that need to be addressed further in obtaining adaptive and scalable OpenFlow-SDN flow control.