This chapter describes the software-defined networking technology used by cloud data center networks to tackle the challenges introduced by the cloud computing architecture. Cloud computing introduces revolutionary changes to traditional operations and customer experience, and seizing the opportunities of cloud computing will boost growth throughout the industry. Cloud computing services can be classified into Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS), which correspond to hardware, software platform, and application resources, respectively. As IaaS systems become more automated and elastic, and as new software technologies such as distribution, service-orientation, Cloud Native, and Service Less continue to emerge, SaaS/PaaS systems are being subverted, and IT software is undergoing an accelerated transformation to Internet software. In the future, as the development of automation, big data, and cloud technologies continues, autonomous networks will gradually be put into practice, once again driving the rapid development and evolution of the entire industry.