1. A method of managing storage of flow data in a packet processing equipment, said including a fast access internal memory and a slower access external memory and configured to process a packet stream that is a random aggregate of a plurality of distinct flows of packets, said method comprising: receiving a data packet at an input of the packet processing equipment, extracting a flow ID from a data packet header of the data packet and mapping the flow ID to an address at which corresponding flow data are stored in the slower access external memory; determining if said received data packet corresponds to a new flow, if said received data packet is a first packet of the flow, creating a new flow data record in the slower access external memory; if at least one other data packet of the flow has been received in the packet processing equipment, determining if a flow data corresponding to said received data packet is available in the fast access internal memory; if the corresponding flow data to said second data packet is available in the fast access internal memory, locating said flow data; if no corresponding flow data to said second data is available in the fast access internal memory, retrieving said corresponding flow data from the slower access external memory and storing them in the fast access internal memory; achieving packet processing using the corresponding flow data from the fast access internal memory, when no more packet of the flow are located in the packet processing equipment; updating the corresponding flow data in the slower access external memory from the flow data in the fast internal memory; and securing the corresponding flow data update.