IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. The Internet Group Management Protocol (IGMP) is a protocol that allows several devices to share one IP address so they can all receive the same data. Protocol-Independent Multicast (PIM) is a family of multicast routing protocols for Internet Protocol (IP) networks that provide one-to-many and many-to-many distribution of data over a LAN, WAN or the Internet.
Types of PIM
PIM Sparse-Mode : In PIM sparse mode (PIM-SM), the assumption is that very few of the possible receivers want packets from a source, so the network establishes and sends packets only on branches that have at least one leaf indicating (by message) a desire for the traffic.
PIM Dense-Mode : PIM Dense Mode (PIM-DM) is the PIM mode which uses Push Model. According to this model, firstly all the multicast traffic is flooded through the recipients. All the nodes in the network receives this traffic even if they are not related in that multicast traffic
Bidirectional PIM : In bidirectional PIM, multicast groups are carried across the network over bidirectional shared trees. This type of tree minimizes the amount of PIM routing state information that must be maintained, which is especially important in networks with numerous and dispersed senders and receivers.
PIM Source-specific Multicast: PIM Source Specific Multicast is a multicast method in which, receivers receive multicast traffic from a specific multicast source as its name implies.
Anycast RP allows two or more rendezvous points (RPs) to share the load for source registration and the ability to act as hot backup routers for each other.
MSDP is a mechanism to connect multiple PIM-SM domains. The purpose of MSDP is to discover multicast sources in other PIM domains