An effective network layer which reduces cluster file system complexity is definitely needed in cluster computing environments where more than thousands of nodes are connected on a variety of different networks. Therefore, widely used cluster file systems such as Lustre, PVFS2, and GlusterFS provide networking virtualization layer. Through networking virtualization layer, each node accesses other nodes using a single interface over a variety of networks. However, previous networking virtualization technologies are complicated and not portable. In this paper, we propose a simple, portable, and socket-like networking virtualization layer that operates on user-mode. We also evaluate our virtualization layer using benchmark tools.