Data centers have undergone significant expansions in recent years, as cloud service providers seek to improve the quality of service and reduce operational costs. Cloud providers are investing heavily in inter-data center wide-area networks, which help to transport traffic between geographically distributed data centers. However, efficient workload management in complex large-scale networks with a dynamic environment is challenging. In this regard, researchers have developed various solutions to address different challenges for data transfer in inter-data center networks. In this paper, we present a comprehensive review of recent strategies and optimization schemes proposed in the literature to optimize data transfer in geographically distributed data centers. This review paper examines the challenges of data delivery and classifies recent existing solutions for addressing the issues based on communication patterns, objectives, proposed communication frameworks, and evaluation methods. In this study, we provide valuable insights into the current challenges and identify several promising research directions that require significant research endeavors in the future. The findings of this study are useful for researchers and practitioners interested in optimizing data transfer in inter-data center networks.