Configuring Multicast Vlans - HP A8800 Configuration Manual

Configuring multicast VLANs

Overview
As shown in
to different VLANs, Host A, Host B, and Host C require the same multicast program on demand service
simultaneously, Router A needs to forward a separate copy of the multicast data in each user VLAN to the
Layer 2 device, Device A. This results in waste of network bandwidth and extra burden on the Layer 3
device.
Figure 20 Multicast transmission without multicast VLAN
Source
The multicast VLAN feature is the solution to this issue. With the multicast VLAN feature, the Layer 3
device needs to replicate the multicast traffic only in the multicast VLAN instead of making a separate
copy of the multicast traffic in each user VLAN. This saves the network bandwidth and lessens the burden
of the Layer 3 device.
The device supports the sub-VLAN-based multicast VLAN feature.
As shown in
configure VLAN 10 as a multicast VLAN, configure all user VLANs as sub-VLANs of this multicast VLAN,
and enable IGMP snooping in the multicast VLAN.
Figure 20, in the traditional multicast programs-on-demand mode, when hosts that belong
Multicast packets
VLAN 2
VLAN 3
VLAN 4
Router A
IGMP querier
Figure 21, Host A, Host B and Host C are in three different user VLANs. On Device A,
VLAN 2
VLAN 3
Device A
VLAN 4
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Receiver
Host A
Receiver
Host B
Receiver
Host C