Abstract

The rapid expansion of cloud computing has given rise to a complex multi-domain environment, where various cloud platforms (public, private, hybrids) need to be originally integrated. Since organizations adopt multi-cloud strategies rapidly, the development of protocol architecture becomes important to ensure efficient, safe and scalable communication in asymmetrical cloud domains. This paper explores the historical development of cloud computing, ranging from early single-domain systems to modern multi-domain cloud environments. It examines the major protocol employed in this environment and analyses their strengths, boundaries, and challenges that they address, such as scalability, interoperability, and safety. In addition, the paper examines the impact of emerging technologies such as software-defined networking (SDN), network functions virtualization (NFV), and edge computing on the development of the architecture. Through the case study and performance evaluation, the work highlights the progress made in protocol design, with a focus on practical applications and future instructions for cloud protocol architecture in a multi-domain context.