A framework for internet group communications services

IP multicast shows a very strong advantage in the group communication services. To deploy IP multicast in the current Internet, every IP router must be changed into multicast enabled ones and several deployment issues should be solved. These problems prevent IP multicast mechanism from being deployed in the IP world. These problems gives a good reason why today's group communication uses replicated IP unicast mechanism instead of IP multicast. Recently an overlay multicast is proposed as an alternative method of IP multicast. We propose a RMCP (relayed multicast protocol) as an application-layer protocol for providing end-to-end multicast services over IP-network environment. We also push RMCP into ITU-T and ISO standardization activity. In this paper we define the basic concepts of relayed multicast scheme, data delivery models, service scenarios and standardization activities on RMCP