A reliable multicast protocol for real-time continuous-media streams on switch Ethernet after research of the LANs special features for reliable multicast is proposed. The recovery of this protocol begins with the receivers detection of packet loss by packets number, and the second step of it is the NAK (negative acknowledgment) suppression procedure, and then the sender will retransmit the lost packet by the received NAK, and finally the receiver will discard or accept the recovered packet based on the limit of the real-time playback. The experimental results and the analysis of performance demonstrate the effectiveness and reliability of the approach.