Overview of IGMP
In the TCP/IP protocol suite, the Internet Group Management Protocol (IGMP) manages IPv4 multicast members, and sets up and maintains multicast member relationships between IP hosts and their directly connected multicast routers.
IGMP is a signaling mechanism used by IP multicast on the end network. IGMP is applicable to both the host side and router side:
On the host side, IGMP allows hosts to dynamically join and leave multicast groups anytime and anywhere.
A host's operating system (OS) determines the IGMP version that the host supports.
On the router side, IGMP enables a router to determine whether multicast receivers of a specific group exist. Each host stores information about only the multicast groups it joins.
IGMP has three versions, as listed in Table 1.