Since the cloud computing technology is commonly developed, some new inventions of the Internet are required to operate in hybrid architecture with both virtualized and physical components. To evaluate these kinds of innovations in testbeds, the ability of emulation is the key point. This paper presents a prototype design implemented in a network testbed for providing virtual nodes. By doing this, testbed users can request physical or virtual nodes to establish their experiments. This paper will demonstrate a case study deployed at Testbed@NCKU, expecting to enhance the ability of the emulation of this testbed. The aim of this paper is to illustrate a way and to share the experience of improving the network testbed to support virtual nodes for testbed users.