The Internet Group Management Protocol (IGMP) is a communication protocol used by hosts and adjacent routers on an Internet Protocol (IP) network. Its primary function is to manage the membership of Internet Protocol multicast groups, allowing devices to join or leave these groups efficiently. This is essential for applications that send data to multiple recipients simultaneously, such as streaming video or online gaming. IGMP operates at the network layer of the Internet Protocol Suite and is crucial for optimizing network traffic. By enabling routers to determine which devices are interested in receiving multicast traffic, IGMP helps reduce unnecessary data transmission, improving overall network performance and resource utilization.