3Com WX3000 Displaying and Maintaining Igmp Snooping, Igmp Snooping Configuration Examples

zOne port can belong to only one multicast VLAN.

zThe port connected to a user terminal must be a hybrid port.

zThe multicast member ports must be in the same VLAN with the router port. Otherwise, the multicast member port cannot receive multicast packets.

zIf a router port is in a multicast VLAN, the router port must be configured as a trunk port or a hybrid port that allows tagged packets to pass for the multicast VLAN. Otherwise, all the multicast member ports in this multicast VLAN cannot receive multicast packets.

zWhen the multicast VLAN is set up, all IGMP report messages are forwarded to the router ports in the multicast VLAN. If no router ports exist in the multicast VLAN, all IGMP report messages are flooded within the multicast VLAN.

Displaying and Maintaining IGMP Snooping

To do…	Use the command…	Remarks
Display the current IGMP	display igmp-snooping
Snooping configuration	configuration
Display IGMP Snooping	display igmp-snooping	Available in any view
message statistics	statistics
Display the information about	display igmp-snooping group
IP and MAC multicast groups in
one or all VLANs	[ vlan vlanid ]
Clear IGMP Snooping statistics	reset igmp-snooping statistics	Available in user view

IGMP Snooping Configuration Examples

Configuring IGMP Snooping

Network requirements

To prevent multicast traffic from being flooded at Layer 2, enable IGMP Snooping on Layer 2 devices.

zAs shown in Figure 2-3, Router A connects to a multicast source (Source) through GigabitEthernet1/0/2, and to Switch A through GigabitEthernet1/0/1.

zRun PIM-DM and IGMP on Router A. Run IGMP snooping on Switch A. Router A acts as the IGMP querier.

zThe multicast source sends multicast data to the multicast group 224.1.1.1. Host A and Host B are receivers of the multicast group 224.1.1.1.

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