Performance Analysis of POX and OpenDayLight Controllers Based on QoS Parameters Houda Hassen (B ) , Soumaya Meherzi, and Safya Belghith RISC Laboratory, National Engineering School of Tunis, University of Tunis El Manar, Tunis, Tunisia {houda.hassen,soumaya.meherzi,safya.belghith}@enit.utm.tn Abstract. Software-defined networking (SDN) is an emerging network architecture that has been recently proposed to address the limitations of traditional networks. SDN consists in decoupling the forwarding plane and the control plane and moving this latter to a remote controller, which manages traffic routing rules in a centralized and dynamic fashion. Thus, the controller plays a crucial role in network management operations. A large diversity of open-source controllers, with different features, has been proposed for both industrial and research purposes. Extensive efforts are being deployed to provide a comparative study between available open- source controllers through performance evaluation of underlying SDN networks. In this paper, we provide an overarching performance evalua- tion of two popular SDN controllers namely, POX and OpenDayLight. Based on Mininet emulator, we assess the most relevant QoS parame- ters between end nodes in SDN networks namely, throughput, round trip time, jitter and packet loss. Moreover, we compare the behavior of the considered controllers within different network topologies such as, single, tree, linear and custom topologies. Keywords: Software defined network · Controller · OpenFlow · OpenDayLight · POX · QoS 1 Introduction Network Function virtualization (NFV) and software defined networking (SDN) are the two most prominent key enablers for next generation networks to over- come the limitations of traditional networks. Indeed, such technologies provide a high level of flexibility, programmability and scalability to network-management and -orchestration operations in a cost-effective way. From one hand, NFV per- forms the virtualization of network resources, functions and services, which offers an abstraction representation of the network components. From the other hand, SDN, which is based on the separation of the control plane and the forwarding plane, centralizes network management operations in a software-based controller. c  The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 L. Barolli et al. (Eds.): AINA 2021, LNNS 226, pp. 745–756, 2021. https://doi.org/10.1007/978-3-030-75075-6_61