Routing optimization strategies in data center networks: A survey

As a critical component of cloud and distributed computing infrastructures, optimizing routing strategies in Data Center Networks (DCNs) is crucial for ensuring high bandwidth, low latency, high reliability, and energy efficiency. However, traditional routing policies encounter significant challenges in addressing dynamic traffic patterns, cross-domain transmissions, and the increasing demands for green computing, necessitating systematic analysis and innovative optimization. This paper presents a comprehensive review and classification of existing routing strategies, addressing the gap in current research regarding the applicability and systematic comparison between intra-DCN and inter-DCN environments. Notably, intra-DCNs and inter-DCNs differ significantly in their architectural characteristics, operational requirements, and functional objectives, which necessitates tailored routing strategies for each domain. We proposed a novel framework for classifying routing policies. For intra-DCNs, we examined core policies across six dimensions: load optimization, traffic scheduling, congestion control, intelligent optimization, fault-tolerant, and energy efficiency. For inter-DCNs, the analysis covers routing strategies focused on load balancing, traffic scheduling, fault-tolerant, energy efficiency, and intelligent optimization. Through comparative analysis, this paper underscores the strengths and limitations of existing strategies, providing researchers with a comprehensive framework for advancing this field. Additionally, we outlined future research directions. The contribution of this paper lies in offering theoretical support and practical guidance for routing strategy design in both academia and industry, promoting the development of efficient, low-latency data transmission technologies, and guiding DCNs optimization in emerging scenarios such as 5G and edge computing.