What does IGMP do in multicast networks?

In multicast networks, Internet Group Management Protocol (IGMP) plays a crucial role in maintaining group membership between hosts and routers. When devices want to receive a multicast stream, they must join a specific multicast group, and it is IGMP that facilitates this communication. It allows hosts to inform their local router that they wish to receive data addressed to a particular multicast group.

IGMP operates at the network layer and is essential for enabling efficient delivery of multicast traffic. The communication process involves sending IGMP messages to join or leave multicast groups. This way, routers can track which devices are interested in receiving certain multicast streams and can handle the distribution of that traffic accordingly. By effectively managing these group memberships, IGMP ensures that multicast data packets are sent only to those devices that have expressed interest, thus optimizing network resources and reducing unnecessary data transmission.