Abstract: Aspects of the disclosure provide a method for packet processing. The method includes receiving a plurality of packets at a port of a network device. The plurality of packets belong to a packet flow having a sequence within a stream of packets. The method then includes mapping identifications respectively allocated to the plurality of packets into a data structure of ordered identifications to maintain the sequence, and generating a new packet instance during processing of a specific packet. The specific packet has a specific identification and is one of the plurality of the packets. Then, the method includes inserting a new identification allocated to the new packet instance into the data structure of ordered identifications next to the specific identification to maintain the sequence and transmitting the plurality of packets and the new packet instance from the network device according to the sequence maintained in the data structure.