Abstract: Videoconferencing and other peer to peer real time distributed applications require real time symmetrical multipoint transfer. Multicast trees of each participants will consume a large quantity of resources, and cannot meet fully the need of symmetrical multipoint transfer in the “closed type” group communication. Therefore, a multipoint connection （MC） architecture is proposed in the paper. An MC which connects all participants may be regarded as being constituted by “merging all directed multicast trees”. A multicast tree is built on the MC when a participant multicasts data to others. Hence, multicast routing procedure is divided into two parts in order, that is to say, building MC on the backbone and building multicast tree on the MC. The manner reduces greatly the whole complexity of building multicast trees during the multipoint session and supports well the rapid switch of floor. The architecture meets well the need of symmetrical transfer in the multipoint session like videoconferencing, and is efficient. The paper also takes advantage of the hierarchical graph representation of networks to simplify and reduce the computational complexity of building MC, and an algorithm for building MC based on the hierarchical graph representation is proposed in the appendix of the paper.