Maintenance of message distribution trees in a communications network
 Each node in a multinode communication system is provided with programming to act as a Set Manager for a given set of nodes and users. Functions of the Set Manager include operation processes for creating distribution trees for efficient multicast and bandwidth reservation tasks. Because set membership is not necessarily fixed or accurate at the time the distribution tree is created, the Tree Leader task that creates and maintains the trees needs accurate and updated information showing the number of users at the nodes it serves which are participating in the distribution tree. The count of active users at nodes served by the Tree Leader is provided in response to an indicia established at the time the Tree Leader sets up the tree. Each Set Manager at a given node monitors for changes in set membership and link failure and notifies the requesting Tree Leaders for each tree in which it participates whenever changes in the number of users either by joining or leaving the set or link failures occur by direct communication between the Set Managers and the Tree Leaders without requiring intervention of other elements in the system. 
International Business Machines Corp.
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Elizabeth A. John E.
Hervatic Drake, Jr.