An architecture and associated protocols are presented for managing multicast addresses and performing connection control for applications that use multicast communication facilities. A scheme to partition the multicast address space on the basis of the network number is proposed an underlying IP-based internetworking environment is assumed, and its performance and scaling characteristics are discussed. A protocol is then developed to provide for dynamic allocation and release of multicast addresses, as well as maintaining state information for a connection. The protocol is independent of the address partitioning scheme, and hence is essentially applicable to any network layer; it is also shown to be robust and e cient. Finally, we describe two di erent mechanisms, namely address-based ltering and virtual port numbers, which enable the use of a common port number by all session participants.