Multicast VPN extranet distribution allows multicast traffic to flow across different routing instances. A routing instance that received a PIM/IGMP JOIN but cannot reach source of multicast source directly within its own instance is selected as receiver routing instance (receiver C-instance). A routing instance that has source of multicast stream and accepts PIM/IGMP JOIN from other routing instances is selected as source routing instance (source C-instance). A routing instance that does not have either source or receivers but is used in the core is selected as a transit instance (transit P-instance). The following subsections detail supported functionality.