Along with rapid growth of mobile internet

cloud computing and other new services

on the one hand

the traditional IDC is being transformed to cloud computing data center

on the other hand

more and more applications and data are coming to be carried on the cloud

which makes the scale of cloud data centers substantially increase

while the traditional network architecture and the technologies has been difficult to adapt to the development of the cloud data center. As a recent rising new network technology

SDN is considered to be an important mean to solve many network problems of cloud data center. Major challenges and problems of data center network were analyzed after introducing cloud computing and then proposals to solve them were given. After comparing several classic SDN technologies

the solution of cloud data center network based on overlay SDN was proposed

and its implementation principle was deeply analyzed. Finally

the development trend of the cloud data center network was discussed.