Internet Group Management Protocol (IGMP) is a protocol that runs between hosts and their immediate neighboring multicast routers. The protocol allows a host to inform its local router that it wishes to receive transmissions addressed to a specific multicast group. Based on group membership information learned from the IGMP, a router is able to determine which if any multicast traffic needs to be forwarded to each of its subnetworks.

A protocol used to form and dissolve groups on the MBONE.

A network-layer protocol for managing multicast groups on the Internet.