Microsoft Installation, Storage, And Compute With Windows Server 2016 (70-740) Practice Test

The key idea is how multicast traffic is delivered efficiently in a switched network. By default, switches can’t tell which hosts want to receive a multicast stream, so they may flood that traffic to every port in the VLAN. IGMP (Internet Group Management Protocol) provides a mechanism for hosts to join or leave multicast groups. When a switch uses IGMP snooping, it listens to these IGMP reports and builds a per-group map of which ports have listeners. With this information, the switch forwards multicast frames only to the ports that have members of the group, not to every port. This targeted delivery prevents unnecessary flooding and reduces unnecessary load on the network. Other options don’t provide this selective delivery: unicast is a one-to-one delivery, multicast without filtering can flood, and broadcast goes to all ports indiscriminately. Using IGMP (via snooping) is the mechanism that minimizes flood for multicast traffic.