Optimisation Methods for the Controller Placement Problem in SDN: A Survey

Abstract

Software-defined networking (SDN) has emerged in response to increasing requirements for new networks and expansion of Internet coverage. Modern needs exceed the limitations of traditional networks, for which, to simplify management, SDN is proposed as a promising paradigm that separates the control and data planes, allowing for the programming of network configuration. SDN deployment and applications are directly affected by the controller position. Single or multiple controllers are used in SDN architecture to enable programmable, flexible, and scalable configurations. Multiple controllers are essential in the current SDN, and various solutions have been recently developed to improve scalability and placement selection. In this study, the Controller Placement Problem (CPP) is explored using objective optimisation with proposed algorithms. An overview of SDN issues and the controller role is provided through its three-plane architecture with a focus on scalability and reliability. In addition, a comprehensive problem review is discussed on the basis of a well-known compendium of available solutions. Finally, relevant open problems and future research challenges are identified.