Method and apparatus for hierarchical discovery and pruning of slow members of a multicast group

A method and system for pruning slow multicast group members in a multicast group that includes a sending node and member nodes. The sending node and selected ones of the other nodes comprise repair heads of a repair tree. Each repair head has at least one child. Each of the member nodes generates a slowness metric. Each member node repair head aggregates its own slowness metric with the slowness metrics of their respective children in the tree along with a subtree flag that indicates whether the respective slowness metric is due to the reporting node or a node downstream of the reporting node. The member node repair heads propagates the largest of the aggregated slowness metrics upstream along with a subtree flag associated with the propagated slowness metric. Via this process the sending node receives the largest slowness metrics generated in respective branches of the repair tree along with corresponding subtree flags associated with the respective metrics. In response to the receipt of an indication of congestion at one or more of the member nodes when the sending node is transmitting at a minimum acceptable data rate, the sending node initiates pruning of slow group members in a predetermined manner. The globally largest slowness metric is employed in conjunction with the aggregated slowness metrics and associated subtree flags retained at the sending node and intermediate nodes to identify slow member nodes within the multicast group that should be pruned.