QoS control in group communication

This paper discusses a communication model to exchange multimedia messages in a group of multiple processes. Quality of Service (QoS) required by an application has to be supported. In traditional communication protocols like TCP and RTP, a process can reliably deliver messages to one or more than one process, i.e. one-way transmission. In the group communication, a process sends multimedia messages to multiple processes while receiving multimedia messages from multiple processes in a group. In addition, messages are required to be causally delivered. We discuss how to transmit multimedia messages to each destination process so as to satisfy QoS requirement.