A fleet garage floods mDNS-like multicast onto every access port until operators enable a Layer-2 feature that learns interested ports from IGMP joins. What does that feature primarily accomplish?
Select an answer to reveal the explanation.
Short Explanation
Without help, a switch treats multicast like a party flyer and stuffs it in every mailbox on the floor. IGMP snooping listens for who actually RSVP’d and only delivers to those ports. Turn it on and the garage stops drowning in unwanted group traffic.
Full Explanation
IGMP snooping inspects IGMP membership reports and leaves so the switch builds a Layer-2 multicast forwarding table keyed by group (and often VLAN). Frames for that group are forwarded only toward interested ports and the multicast router port, rather than being flooded to all ports in the broadcast domain. This is a standard L2 optimization and does not by itself replace PIM routing or create static mroutes.