Abstract: A method and a network node for traffic shaping of a packet switched network is presented, the network node being arranged for processing packets to be transmitted in the network according to at least: —a serial packet processing algorithm Aser providing a synchronized utilization of a set of at least one processing unit; and—a parallel packet processing algorithm Apar providing an at least partly unsynchronized utilization of the set of at least one processing unit; wherein—the processing of the packets corresponds to a total packet cost, which is cooperatively shared by the at least one processing unit of the set.