Due to the increasing heterogeneity in network user requirements, dynamically varying day to day network traffic patterns and delay in network service deployment, there is a huge demand for scalability and flexibility in modern networking infrastructure, which in return has paved way for the introduction of Software Defined Networking (SDN) in core networks. In this paper, we present an FPGA-based switch which is fully compliant with OpenFlow; the pioneering protocol for southbound interface of SDN. The switch architecture is completely implemented on hardware. The design consists of an OpenFlow Southbound agent which can process OpenFlow packets at a rate of 10Gbps. The architecture contains a primary pipeline which is capable of achieving core network throughputs and an auxiliary pipeline leading to the Openflow agent. Single clock cycle Content Accessible Memory (CAM) architecture supports the overall design to achieve its throughput and latency requirements. The proposed architecture speed scales up to 400Gbps while it consumes only 60% resources on a Xilinx Virtex-7 featuring XC7VX485T FPGA. Switch fabric is capable of connecting to a control plane running upon a host PC via PCIe which provides an opportunity at research level to explore SDN in core networks. Moreover, the architecture is experimented for different scaled versions using line rates of 10G, 25G and 100G. By using FPGA based embedded platforms which support sufficient number of ports and their line rates, this architecture can be deployed in core networks.