Method to optimize flow-based network function chaining

In a forwarding network comprising a function chain network controller, a plurality of intermediate network functions (NFs) and flow-based chain selectors (FBCSs) forming VNFs and configured to transfer data packets via a plurality of links, a method comprising a FBCS requesting substitution in the header representation of function chain entries of a data packet header in a flow with a different representation of function chain entries, wherein the flow bypasses at least one intermediate FBCS based on the substituted function chain entries representation. The function chain network controller discovers FBCS capable nodes and their topology, and maintains a function chain substitution state and distributes it to the FBCS relevant substitutions. The function chain network controller distributes a list of adjacent FBCSs to the FBCS, and distributes a list of abstracted adjacent FBCSs to the FBCS and translates requests from an abstracted value to a real value.