A grouping model for distributed real time causal ordering

This paper proposes a dynamic hierarchical architecture of k-local groups, where k represents the number of local groups composing the group communication system S. Each local group is defined as a finite set of processes. The proposed architecture ensures real-time causal ordering between alive local group members. This structure allows us to compensate for the local clock drift by synchronizing the local clocks, and ensures real-time causal delivering. We validate this model by using CPN tools (coloured Petri nets) to obtain a state space graph. The objective is to study the behaviour of this model, by verifying different properties such as boundedness and liveness. Simulation results show that the hierarchical architecture respects all studied properties. Therefore the real-time causal ordering is guaranteed