Cisco ENCOR Practice Exam 2025 – All-in-One Comprehensive Guide to Mastering Enterprise Network Core Technologies!

The primary purpose of IGMP snooping is to determine multicast group memberships. IGMP, or Internet Group Management Protocol, is used by hosts and adjacent routers on an IP network to establish multicast group memberships. By enabling IGMP snooping on a switch, the switch can listen in on IGMP communications between hosts and routers to learn which devices are interested in receiving multicast traffic. This allows the switch to forward multicast frames only to the ports that contain members of the multicast group instead of flooding the traffic to all ports. This targeted delivery of multicast traffic significantly reduces unnecessary load on the network and optimally utilizes bandwidth.

While other options relate to network traffic management, they do not capture the specific role of IGMP snooping in handling multicast traffic directly. Managing unicast traffic pertains to individual connections rather than group memberships. Optimizing broadcast traffic provides a broader traffic management concept but does not directly focus on the specific functionality of managing multicast. Preventing unauthorized access involves security measures that are not the primary focus of IGMP snooping. Thus, determining multicast group memberships captures the essential role that IGMP snooping plays in network management.