Forwarding Metamorphosis: Fast Programmable Match-Action Processing in Hardware for SDN
In Software Defined Networking (SDN) the control plane is physically separate from the forwarding plane. Control software programs the forwarding plane (e.g., switches and routers) using an open interface, such as OpenFlow. This paper aims to overcome two limitations in current switching chips and the OpenFlow protocol: current hardware switches are quite rigid, allowing \"Match-action\" processing on only affixed set of fields, and the OpenFlow specification only defines a limited repertoire of packet processing actions. The authors propose the RMT (Reconfigurable Match Tables) model, a new RISC-inspired pipelined architecture for switching chips, and they identify the essential minimal set of action primitives to specify how headers are processed in hardware.