Associating a Multicast VLAN with Specified User VLANs

If users in different VLANs are interested in data from the same multicast source, create a multicast VLAN on a Device and associate this multicast VLAN with the user VLANs. Then, the Device uses the multicast VLAN to manage the multicast source and multicast group members, simplifying multicast management and improving bandwidth usage.

Context

The multicast VLAN function involves two concepts: multicast VLAN and user VLAN.

A multicast VLAN is a VLAN to which router interfaces connected to multicast sources belong. A multicast VLAN is used to aggregate multicast flows. A router allows you to configure a maximum of 128 multicast VLANs.
A user VLAN is a VLAN to which user hosts belong. A user VLAN is used to receive data from a multicast VLAN.
A multicast VLAN can be associated with a maximum of 4093 user VLANs.

Procedure

Run system-view
The system view is displayed.
Run vlan vlan-id
A multicast VLAN is created, and the multicast VLAN view is displayed.
Run igmp-snooping enable
Internet Group Management Protocol (IGMP) snooping is enabled for the multicast VLAN.
Run multicast-vlan enable
The multicast VLAN function is enabled.
Run multicast-vlan user-vlan { { vlan-id1 [ to vlan-id2 ] } &<1-10> }
The multicast VLAN is associated with the specified user VLANs.

A multicast VLAN can be associated with multiple user VLANs, but a user VLAN can be associated with only one multicast VLAN.
(Optional) Run multicast-vlan igmp-querier-election user-vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>
Querier election is enabled for the user VLANs.

If two routers are connected to the same user VLAN and the multicast VLAN function is enabled, the user VLAN will receive two copies of identical multicast data from the two routers, consuming bandwidth resources. To resolve this issue, run the multicast-vlan igmp-querier-election user-vlan command to enable the querier election function for user VLANs. With this function enabled, the router that does not win a querier election will delete forwarding entries and will not create forwarding entries after receiving Report messages from user VLANs. As a result, the router will not send multicast data to the user VLAN.

Before enabling querier election, ensure that the igmp-snooping send-query source-address command has been run on each router to configure a source IP address for the IGMP Query messages to be sent by the querier.
(Optional) Run igmp-snooping send-query source-address ip-source-address
A source IP address for the IGMP Query messages sent by a device is set.

By default, the source IP address of the IGMP Query messages sent by the device is 192.168.0.1. In some scenarios, the IP address may be used by another device, or users require that the source IP address of IGMP Query messages be on the same network segment as the IP address of the local device. In this case, you can run the igmp-snooping send-query source-address command to set a source IP address for the IGMP Query messages sent by the device.
(Optional) Run multicast-vlan send-query prune-source-port
Sending General Query messages back through the source interface in the user VLAN is disabled.

When the multicast VLAN and the user VLAN are configured on the same interface, general query packets are forwarded back through the interface by default. The source MAC address of the packet is not changed during the forwarding process. Therefore, the upstream device learns the MAC address table of the interface as the source MAC address. If the upstream device has learned the source MAC address from another interface, MAC address flapping occurs on the upstream device. To avoid this situation, perform this step.
Run port isolate-state exclude multicast
Multicast traffic and packets are not isolated in the VLAN.
Run commit
The configuration is committed.