Metaheuristic solutions for solving controller placement problem in SDN-based WAN architecture

Software Defined Networks (SDN) is a popular paradigm in the modern networking systems that decouples the control logic from the underlying hardware devices. The control logic has implemented as a software component and residing in a server called controller. To increase the performance, deploying multiple controllers in a large-scale network is one of the key challenges of SDN. To solve this, authors have considered controller placement problem (CPP) as a multi-objective combinatorial optimization problem and used different heuristics. Such heuristics can be executed within a specific time-frame for small and medium sized topology, but out of scope for large scale instances like Wide Area Network (WAN). In order to obtain better results, we propose Particle Swarm Optimization (PSO) and Firefly two population-based meta-heuristic algorithms for optimal placement of the controllers, which take a particular set of objective functions and return the best possible position out of them. The problem has been defined, taking into consideration both controllers to switch and inter-controller latency as the objective functions. The performance of the algorithms evaluated on a set of publicly available network topologies in terms execution time. The results show that the FireFly algorithm performs better than PSO and random approach under various conditions.