Abstract: A system for reliable multicast transmission [multicasting data packets] in a packet-based data network includes mechanisms for performing the following: (1) preparing at least one packet comprising a payload portion and multicast route information, an error detection mechanism; (2) transmitting the packet to at least one intermediate node for delivery to at least two destination nodes; (3) waiting for a period of time for at least one acknowledgment signal indicating receipt of the at least one packet by at least one destination node; and (4) retransmitting a packet to a set of destination nodes from which no positive acknowledgment has been received. The multicast routing information includes information for use by the at least one intermediate node to forward the packet to at least two destination nodes.