Recently, a variety of solutions have been proposed to tackle the controller placement
problem in SDN. The objectives include minimizing the latency between controllers and their
associated switches, enhancing reliability and resilience of the network, and minimizing
deployment cost and energy consumption. In this article, we first survey the state-of-the-art
solutions and draw a taxonomy based on their objectives, and then propose a new
approach to minimize the packet propagation latency between controllers and switches. In …

A distinctive feature of software‐defined networking (SDN) is a logically centralized control
plane realized using multiple physical controllers. The placement of the controllers, the so‐
called controller placement problem (CPP), is a crucial design issue. It influences network
performance parameters such as latency, flow setup time, network availability, load balance
of the controllers, and energy consumption. In this article, we illustrate the formulation of
these CPP objectives. We categorize the CPP design solutions as either static or adaptive …