Alcatel-Lucent Verizon BT Deutsche Telekom NTT Communications More that one set of mechanisms to support multicast in a layer 3 BGP/MPLS VPN has been defined. These are presented in the documents that define them as optional building blocks. To enable interoperability between implementations, this document defines a subset of features that is considered mandatory for a multicast BGP/MPLS VPN implementation. This will help implementers and deployers understand which L3VPN multicast requirements are best satisfied by each option. This document is not an Internet Standards Track specification; it is published for informational purposes.