The Internet Group Management Protocol (IGMP) is an Internet protocol that provides a way for an Internet computer to report itsmulticast group membership to adjacent routers. Multicasting allows one computer on the Internet to send content to multiple other computers that have identified themselves as interested in receiving the originating computer’s content. Multicasting can be used for such applications as updating the address books of mobile computer users in the field, sending out company newsletters to a distribution list, and “broadcasting” high-bandwidth programs of streaming media to an audience that has “tuned in” by setting up a multicast group membership.
Using the Open Systems Interconnection (OSI) communication model, IGMP is part of the Network layer. IGMP is formally described in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 2236.
The Internet Group Management Protocol (IGMP) is a communications protocol used by hosts and adjacent routers on IP networks to establish multicast group memberships.
IGMP is an integral part of the IP multicast specification. IGMP can be used for online streaming video and gaming, and allows more efficient use of resources when supporting these types of applications.
IGMP is used on IPv4 networks. Multicast management on IPv6 networks is handled by Multicast Listener Discovery (MLD) which uses ICMPv6 messaging in contrast to IGMP’s bare IP encapsulation.