2-14
It is not recommended to configure this function while the multicast VLAN function is in effect.
Configuring Multicast VLAN
In traditional multicast implementations, when users in different VLANs listen to the same multicast
group, the multicast data is copied on the multicast router for each VLAN that contains receivers. This is
a big waste of network bandwidth.
In an IGMP Snooping environment, by configuring a multicast VLAN and adding ports to the multicast
VLAN, you can allow users in different VLANs to share the same multicast VLAN. This saves bandwidth
because multicast streams are transmitted only within the multicast VLAN. In addition, because the
multicast VLAN is isolated from user VLANs, this method also enhances the information security.
Multicast VLAN is mainly used in Layer 2 switching, but you must make the corresponding
configurations on the Layer 3 switch.
Table 2-18
Configure multicast VLAN on the Layer 3 switch
Operation
Command
Remarks
Enter system view
system-view
—
Create a multicast VLAN and
enter VLAN view
vlan vlan-id
—
Return to system view
quit
—
Enter VLAN interface view
interface
Vlan-interface vlan-id
—
Enable IGMP
igmp enable
Required
By default, the IGMP
feature is disabled.
Return to system view
quit
—
Enter Ethernet port view for the
Layer 2 switch to be configured
interface
interface-type
interface-number
—
Define the port as a trunk or
hybrid port
port link-type
{
trunk
|
hybrid
}
Required
port
hybrid
vlan
vlan-id-list
{
tagged
|
untagged
}
Specify the VLANs to be
allowed to pass the Ethernet
port
port
trunk
permit
vlan vlan-list
Required
The multicast VLAN
defined on the Layer 2
switch must be included,
and the port must be
configured to forward
tagged packets for the
multicast VLAN if the port
type is hybrid.