The present invention relates to a new error control paradigm in a packet switched network that is particularly advantageous for multicast transmission.A transmission Status Vector TSV (T) is updated at the sender side whenever a new outgoing data packet (Dj−1) is scheduled for transmission. A corresponding Reception status Vector RSV (R) is similarly updated at the receive side whenever a new incoming and correctly indexed data packet (Dj−1) is validly received.As soon as a missing or corrupted data packet (Dj) is detected, the update of the RSV is suspended. A request is then sent to the sender to get the current Tsv's value, or a part thereof. The erroneous data packet is then recovered from the current TSV's value (Sk,m), from the lastly updated RSV's value (Sj-1), and from otherwise validly received data packets (Dj+1, . . . , Dk).The present invention more specifically relates to a transmitting unit (100) and a receiving unit (200) implementing that paradigm, and correspondingly to a method for protecting a flow of indexed data packets against data lost or data corruption, and a method for recovering a missing or corrupted data packet within a flow of indexed data packets.