In traditional store and forward protocols, lost packets have no impact on the delivery of other transmitted packets. With network coding, the impact of a packet loss may affect the decoding of other transmitted packets thus affecting the entire process of communication between nodes. In this work, we propose a new network coding model that allows generating, coding, decoding and transmission activities on the packets. Based on this model, the impact of lost packets on buffering and the complexity at the receiving nodes is studied and two new mechanisms are proposed to allow the recovery of lost packets. Compared to traditional linear network coding protocol, our mechanisms provide a significant performance amelioration in terms of number of transmissions required to recover from packet loss.