A plurality of packets are received by a packet processing device, and the packets are distributed among two or more packet processing node elements for processing of the packets. The packets are assigned to respective packet classes, each class corresponding to a group of packets for which an order in which the packets were received is to be preserved. The packets are queued in respective queues corresponding to the assigned packet classes and according to an order in which the packets were received by the packet processing device. The packet processing node elements issue respective instructions indicative of processing actions to be performed with respect to the packets, and indications of at least some of the processing actions are stored. A processing action with respect to a packet is performed when the packet has reached a head of a queue corresponding to the class associated with the packet.