Software-defined Wide Area Network (SD-WAN) is gaining strong momentum as distributed cloud evolves. The new cloud infrastructure requires novel and innovative network technologies based on virtualization, automated resource (e.g. datacenters, VMs, networks) convergence, ultra-high data forwarding performance, and strict network security. To meet the demands, this paper suggests a scheme for logically isolated group network for virtual convergence environment and evaluates its performance in terms of virtual network generation over the de-facto SD-WAN infrastructure deployed on the advanced research network (KREONET), which operates in six distant cities in Korea and the USA.