New challages to the network have been raised by the building of large scale cloud computing data center

and network virtualization is a key to open this Pandora.The paper focuses on the DC network virtualization

which include the "virtualization of control platform" and "virtualization of data platform"

and details these virtualization technologies realization of mainstream network solution providers

mean while

the technical principle of the latest virtualization protocol has been discussed.The author pictures a blueprint for these technologies evolution at the end of the paper.