This article surveys distributed denial-of-service (DDoS) attacks on software-defined networks (SDNs). SDNs separate the control plane from the data plane in computer networks, thus allowing more flexible management of traffic and topology. SDNs are an important advancement of network technology. Because of their centralized control and architecture, they are particularly susceptible to DDoS attacks and other threats. However, precisely because of these same features, they are also very useful in the defense against DDoS attacks.
The article discusses SDN threats in general and DDoS threats specifically. A basic classification divides defenses into defenses against DDoS attacks using SDNs and defenses against DDoS threats to SDNs. This division is used to classify the papers considered in this survey. The main contributions of the article are the tables that describe and compare the defenses proposed and the many references. Section 7, “Research Challenges and Issues,” would have been more insightful if the authors had related it to the solutions proposed to defend against DDoS attacks.
The writing is rather poor and sometimes even misleading. The style is verbose and at times repetitive, while the use of technical terms is often not precise. In summary, this is a useful article for researchers looking for relevant references, but it is not so useful for those wanting a conceptual understanding of the threats and defenses in SDN.