Internet Group Multicast Protocol (Igmp) - Intel 470F - NetStructure Switch User Manual

C H A P T E
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470T Ch2.p65
R 2 Intel® NetStructure

Internet Group Multicast Protocol (IGMP)

Under normal circumstances, multicast traffic is broadcast by the switch to
all ports. For multicast traffic based on TCP/IP using the IGMP protocol,
the switch can optimize the broadcasting of multicast traffic by forwarding
multicast traffic only to ports that require it.
IGMP Snooping is a feature that allows the switch to forward multicast
traffic intelligently. The switch "snoops" the IGMP query and report
messages and forwards traffic only to the ports that request the multicast
traffic. This prevents the switch from broadcasting the traffic to all ports
and possibly affecting network performance.
IGMP Snooping requires a router that learns about the presence of
multicast groups on its subnets and keeps track of group membership.
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