Internet Multicast service extends the Internet point-to-point unicast delivery to a multi-point delivery. Multicasting means that a datagram is sent to multiple sites at more or less the same time. To support real-time multimedia, the minimization of delay without loosing the reliability of the network is required. To achieve this goal, we have proposed to change the architecture of a multicast one-stage network to a multicast hierarchical two-stage network. We have proved that by giving additional functionalities (such as back-up and error correction) to the intermediate sites (i.e. mrouters) ...