An arrangement, system, and method for switching data packet flows in a communication system. A flow processing core classifies packet flows and defines processing flow sequences applicable to the packet flows. A distributing arrangement directs the packet flows to appropriate functional units or processors according to each packet flow's applicable processing flow sequence. The current position of each packet flow in its respective processing flow sequence is indicated. Packet flow sequence information may be determined so that reclassification of already classified packets is avoided.