Multisites Coordination in Shared Multicast Trees

The majority of today's Internet applications relies on point-to-point transmission. In recent years, however, multicast transmission has become the foundation for such applications as multiparty video conferencing, distributed interactive simulations, and collaborative systems. We describe a novel protocol to coordinate multipoint groupwork in the IP-multicast framework. The protocol supports Internet-wide coordination for large and highly-interactive groupwork, relying on transmission of coordination directives between group members across a shared end-to-end multicast tree. We also describe how addressing extensions to IP multicast can be put to use for our multisite coor-