A name model for nested group communication

Group communication permits a single sender to communicate with multiple receivers. A nested group permits one or more of the receivers to be itself a group. Nested groups are particularly useful for reducing communication traffic on internetwork links and supporting subnetwork autonomy. A name graph model is used to characterize nested groups and formalize the problems of loops and duplications. The authors design and analyze a spanning shadow tree algorithm that detects potential loops and duplication. The algorithm is considered static because loops and duplicates are detected at the time of group membership modification rather than at the time a message is sent. The algorithm changes the system-level representation of the name graph in a transparent manner to avoid infinite loops and to suppress duplicated messages. The worst-case message complexity of name graph update operations is on the order of O(|N|²), where |N| is the number of groups in the system. The complexity of updates can be justified, since run-time overhead for actual message communication is reduced