What is the primary purpose of the IGMP protocol?

The primary purpose of the IGMP (Internet Group Management Protocol) is to manage multicast group membership. This protocol is essential for allowing hosts on an IP network to report their multicast group memberships to neighboring routers. When a host wants to join a multicast group, it sends an IGMP message to inform the local router, indicating that it wants to receive traffic for that specific multicast address.

Multicast communication is efficient because it allows a single data stream to be sent to multiple receivers instead of sending multiple individual streams. Therefore, IGMP helps maintain the efficiency of multicast distribution across networks. It enables routers to determine which hosts are interested in which multicast groups, managing the flow of multicast traffic and ensuring that data is only sent to those that request it.

This role in managing group memberships is vital for applications such as streaming media and online gaming, where many users might want to receive the same content at once. Without IGMP, routers would not know which devices wish to listen to which multicast streams, leading to inefficient network utilization and connectivity issues.

The other options relate to functions that IGMP does not perform, such as establishing paths for data packets, handling the routing of data, or securing data via encryption.