Network virtualization is a promising way for network innovation. Efforts have been made to develop virtual network platforms for both network researches and business applications. In this paper, we aim to provide a new solution to address the shortcomings of existing solutions. We propose MAVIN - a MAC address coding based virtual network platform. MAVIN avoids changing the nodes of the current Internet, and can provide high performance virtual networks with user-specified network protocols and link performance parameters. Comparing to existing network virtualization schemes, MAVIN can achieve layer-2 virtualization which has no extra forwarding overhead. We implement the virtual router prototype of MAVIN and establish a real MAVIN platform to evaluate its performance. Evaluation results show that MAVIN can support high performance virtual networks with excellent scalability.