A fast retransmission method by introducing the internal node under better channel condition to join the work of retransmission after the destination node sends out the packet loss indication for unicast services. Extended to serve multicast services, a system comprising a plurality of nodes utilizes the farthest node in each branch from the source to transmit an acknowledge signal when packet loss occurs. The system then enables the closest node to the acknowledging node to retransmit the requested packet, thereby improving the target packet hit rate and data integrity with less retransmission steps.