This document specifies a BGP address family and related procedures
that allow BGP to be used for setting up multicast distribution trees.
This document also specifies procedures that enable BGP to be used for
multicast source discovery, and for showing interest in receiving
particular multicast flows. Taken together, these procedures allow BGP
to be used as a replacement for other multicast routing protocols,
such as PIM or mLDP. The BGP procedures specified here are based on
the BGP multicast procedures that were originally designed for use by
providers of Multicast Virtual Private Network service.