The Soup
IGMP - Internet Group Management Protocol is used by hosts and
routers to tell each other about group membership.
PIM-SM - Protocol Independent Multicast-Sparse Mode is used to
propagate forwarding state between routers.
SSM - Source Specific Multicast utilizes a subset of PIM’s
functionality to guaranty source-only trees in the 232/8 range.
MBGP - Multiprotocol Border Gateway Protocol is used to
exchange routing information for interdomain    RPF
checking.
MSDP - Multicast Source Discovery Protocol is used to exchange
ASM active source information between RPs.