Software defined networking (SDN) is disrupting the traditional networking industry by shifting network control from the physical network devices to the centralized software, thus facilitating scalability, flexibility and efficiency of the network. In the access networks, varied access technologies and massive number of access devices lead to dramatically increased OPEX, which forces operators to find feasible solutions to increase the revenue-expenditure ratio and achieve a sustainable business model. To deal with these challenges, this paper presents a new SDN-based architecture SDVAN for the access network, which provides cost-efficient network control and management with high scalability and customization support. The new architecture SDVAN abstracts control plane of all physical devices to one centralized controller which enables flexible customization of access network through software-defined fashion. The innovative node design implements a simple programmable node which naturally provides elastic support to various access technologies and efficiently improves the resource utilization. In order to automate orchestration of network services, resource modeling and network abstraction methodologies are introduced, which exposes different levels of visibility and controllability based on the trust level. Lastly, SDVAN well implements network slicing function supporting multi-tenancy and multi-version of network appliance. The theoretical analysis and experimental results prove the effectiveness and practicality of the proposed new architecture SDVAN.