A method for operating a flow-based switching system in a network, including at least one network node designed to transport incoming network packets, in particular a switch (20) or a router, wherein the incoming network packets are matched to flows according to predefined policies, wherein a dynamic flow table (40)—primary flow table (50)—containing information about the flows' properties is computed inside the network node or externally and stored in a memory of the network node, is characterized in that another dynamic flow table (40)—backup flow table (60)—is computed and maintained in parallel, wherein the backup flow table (60) is more coarse grained than the primary flow table (50), and wherein the network node switches between employing the primary flow table (50) or the backup flow table (60) depending on the status of predefined observables. Furthermore, a corresponding flow-based switching system is disclosed.