Controller Placement in SDN: An Evaluation of Link Failure-Tolerant Approaches

Software-defined networking (SDN) has emerged as a transformative paradigm in network architecture, offering dynamic control and management capabilities to optimize network operations. One critical aspect of SDN is the strategic placement of controllers, responsible for orchestrating network functions and policies. In dynamic and large-scale networks, the susceptibility to link failures necessitates the consideration of fault tolerance in controller placement strategies. This paper presents an in-depth exploration of existing techniques that address the challenge of controller placement while accounting for link failures in SDN environments. By analyzing the techniques, a summary of various techniques for link failures is provided. Additionally, the problem formulations of techniques on link failure-aware controller placement are discussed. Through this comprehensive survey, the aim is to contribute to a better understanding of the state-of-the-art approaches in this domain, offering valuable insights for designing resilient and efficient SDN infrastructures.