IGMP Join vs PIM Join in Multicast Routing

In multicast networking, the Internet Group Management Protocol (IGMP) and Protocol Independent Multicast (PIM) play significant roles in managing multicast group membership and forwarding traffic.

The IGMP join process involves a host sending an IGMP join message to its local multicast router to express interest in a specific multicast group. The router updates its multicast routing table accordingly and begins forwarding the relevant multicast traffic to the host.

Conversely, the PIM Join/Prune mechanism is utilized by routers in PIM sparse mode. A router sends a PIM join message upstream towards the source or rendezvous point (RP) when it detects interested hosts downstream for a multicast group. This action signals the router's interest in receiving traffic for that multicast group to serve the needs of its connected hosts.

Overall, IGMP joins host-to-router communication, while PIM joins router-to-router communication, ensuring efficient multicast traffic distribution within a network.

https://networklessons.com/multicast/multicast-routing https://networklessons.com/multicast/multicast-pim-sparse-mode https://networklessons.com/multicast/igmp-version-2