A group communication model for distributed real-time causal delivery

With the increase use of the progress of distributed multimedia applications, the ability of networks to handle temporal relationships among media units is becoming more and more important. Yet delay jitter, and the absence of global clock may disrupt these temporal relationships. This paper proposes a hierarchical architecture of k-local groups, where k represents the number of local groups composing the distributed system G. Each local group is defined as a finite set of processes. The proposed architecture allows us to solve the local clocks drift by synchronizing the local clocks. The clocks synchronization is resolved by according to a time reference noted VMT (virtual master time). This hierarchical topology ensures real-time causal ordering, and guarantees a dynamic reconfiguration, in a failure detection, by insuring at least a partial real-time communication between alive local groups.