52
Figure 19
Port-based multicast VLAN
After the configuration, if Switch A receives an IGMP message on a user port, it tags the message with
the multicast VLAN ID and relays it to the IGMP querier, so that IGMP snooping can uniformly manage
the router port and member ports in the multicast VLAN. When Router A forwards multicast data to
Switch A, it sends only one copy of multicast data to Switch A in the multicast VLAN, and Switch A
distributes the data to all the member ports in the multicast VLAN.
For more information about IGMP snooping, router ports, and member ports, see "Configuring IGMP
snooping."
For more information about VLAN tags, see
Layer 2—LAN Switching Configuration Guide
.
Multicast VLAN configuration task list
Task Remarks
Configuring user port attributes
Required
Configuring multicast VLAN ports
Required
Configuring a port-based multicast VLAN
When you configure a port-based multicast VLAN, you must configure the attributes of each user port
and then assign the ports to the multicast VLAN.
A user port can be configured as a multicast VLAN port only if it is an Ethernet port, or Layer 2 aggregate
interface.
In Ethernet interface view or Layer 2 aggregate interface view, configurations that you make are effective
on only the current port. In port group view, configurations that you make are effective on all ports in the
current port group.
Configuration prerequisites
Before you configure a port-based multicast VLAN, complete the following tasks:
Source
VLAN 2
VLAN 3
VLAN 4
Eth1/0/1
Eth1/0/2
Eth1/0/3
Eth1/0/4
Switch A
Multicast packets
Receiver
Host A
Receiver
Host B
Receiver
Host C
Router A
IGMP querier
VLAN 10 (Multicast VLAN)
