Tactical networks have complex communication and computing requirements due to various adverse situations. These networks are often multi-bearer, which means there are multiple communication mediums that can be used for point-to-point communication. However, it is challenging to manage the networking infrastructure in a dynamically changing environment, where communication links are often unreliable. In addition, mission-critical applications have Quality of Service (QoS) requirements that need to be met in diverse networking conditions. Thus, it is critical to make the network resilient to failures while meeting the QoS requirements. As mobile Ad Hoc Network (MANET) protocols can dynamically adapt to network changes due to their distributed architecture, these protocols can be deployed to a multi-bearer tactical network. However, distributed routing and flooding schemes of MANET protocols can consume a high amount of power and cause computational overhead to the communication devices. Software-Defined Networking (SDN) has emerged as a flexible and programmable approach to network management. It enables the dynamic provisioning and reconfiguration of network resources by defining a clear separation between the control and data forwarding planes. The control plane consists of a logically centralized entity called the SDN controller, which has a global view of the network and makes traffic-related decisions. The data forwarding plane consists of network devices such as routers/switches, which are solely responsible for forwarding the network packets. This separation of responsibilities simplifies policy enforcement, allows adaptive network configuration, enables the optimisation of resource allocation, and enhances scalability, among other benefits. However, there are still various challenges that need to be addressed to properly and reliably exploit the benefits of SDN in a multi-bearer tactical network. In particular, in the context of tactical functions, networking takes place among several heterogeneous, dynamic, intermittent, and unreliable communication technologies and between applications with distinct data transmission requirements in terms of QoS and security features.