As a global community, the Internet is comprised of thousands of administrative entities that operate and interact with each other. Transferring data among these entities is possible due to the process of routing, which is challenging due to the lack of centrality. Consequently, the Border Gateway Protocol (BGP) can play a vital role in the routing process as a central hub for disseminating routing information to the various autonomous systems. Yet, the BGP poses security vulnerability due to the difficulty of validation and authentication. Recent studies argue that it would be beneficial to apply the Software-Defined Networking (SDN) approach to address some of the BGP problems. The SDN can help handle BGP-based networks at a low cost and with minimal complexity. However, there are still many scientific and operational problems in this field of study. The main objective of this paper is to identify the challenges that the BGP facing with respect to the adoption of the SDN. The findings revealed that most researchers focused on improving convergence time, while other essential features such as scalability and privacy were overlooked.