Multicast Filtering And Your Switch - 3Com SuperStack 3 3812 Implementation Manual

Multicast Filtering 35
Figure 5 The effect of multicast filtering
Multicast Filtering Your Switch provides automatic multicast filtering support using IGMP
and Your Switch (Internet Group Management Protocol) Snooping. It also supports IGMP
query mode.
Snooping Mode
Snooping Mode allows your Switch to forward multicast packets only to
the appropriate ports. The Switch "snoops" on exchanges between
endstations and an IGMP device, typically a router, to find out the ports
that wish to join a multicast group and then sets its filters accordingly
Your Switch is compatible with any device that conforms to the IGMP v2
protocol. The Switch does not support IGMP v3. If you have an IGMP v3
network, you should disable IGMP snooping for the Switch using the
snoopMode command on the Web Interface.