User Manual Managed Switches
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When an IP host receives a query packet, it sends a report packet back that identifies the
multicast group that the end-station would like to join.
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When the report packet arrives at a port on a switch with IGMP Snooping enabled, the switch
knows that the port should forward traffic for the multicast group, and then proceeds to forward the
packet to the router.
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When the router receives the report packet, it registers that the LAN or VLAN requires traffic for
the multicast groups.
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When the router forwards traffic for the multicast group to the LAN or VLAN, the switches only
forward the traffic to ports that received a report packet.
3.11.2 IGMP Snooping Basic Configuration
IGMP Snooping provides the ability to prune multicast traffic so that it travels only to those end
destinations that require that traffic, thereby reducing the amount of traffic on the Ethernet LAN.
