IGMPv3 Example (future)
In this example, host “H1” has joined group 224.1.1.1 but only wishes to receive traffic from Source 1.1.1.1.  Using an as yet unspecified IGMPv3 mechanism, the host can inform the designated router, “R3”, that it is only interested in multicast traffic from Source 1.1.1.1 for Group 224.1.1.1.  Router “R3” could then potentially “prune” this specific (S,G) traffic source.