1. Method for managing the storage of flow data in a packet processing equipment wherein said equipment processes a packet stream that is a random aggregate of a large number of distinct flows of packets and comprises a fast access internal memory and a slower access external memory and wherein said method comprises: receiving a data packet at the input of the packet processing equipment, extracting a flow ID from the data packet header and mapping it 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 the first of its flow, creating a new flow data record, if at least one other packet of the flow has been received in the packet processing equipment, determining if the flow data corresponding to said received packet is available in the fast access internal memory, if the corresponding flow data is available in the fast access internal memory, locating said flow data, if no corresponding flow 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 corresponding flow data from the fast access internal memory, when no more packet of a given flow are located in the packet processing equipment, updating corresponding flow data in the slower access external memory from the flow data in the fast internal memory, securing corresponding flow data update.