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Aggregation Conflicting goals Scale: Minimize P-router state ? Use as few trees as possible Optimality: Send traffic at most once on each link, and only to PEs that need it ? Use a tree for each customer multicast group Solution: lots of options Draft-rosen has one MDT per VPN, and optional data MDT for high BW or sparse customer groups New draft also allows a tunnel to be shared among multiple mVPNs Better aggregation, less optimality Requires a de-multiplexing field (e.g., MPLS label) Utility of aggregation depends on amount of “congruence” and traffic volume |