Software-defined networking (SDN) is used by most evolving networks, including the Internet of Things, IMT-2020 and next-generation networks, because of its numerous advantages, which include reducing end-to-end data latency and improving availability, reliability and flexibility of the system. To meet their scalability requirements, most of these systems use SDN networks with multi-controller configurations. There are several challenges in this field in particular the multi-vendor issue (software and hardware), interfaces limitations, scalability on the control plane and other related to sustainable multi-controller communication. This Recommendation describes methods for testing SDN multi-controllers based on model networks.