mld-snooping proxy
Function
The mld-snooping proxy command enables Multicast Listener Discovery (MLD) snooping proxy in a VLAN.
The undo mld-snooping proxy command disables MLD snooping proxy in a VLAN.
By default, MLD snooping proxy is disabled in a VLAN.
Usage Guidelines
Usage Scenario
- When the first member joins a multicast group or a host sends a Report message in response to a MLD Query message, the Layer 2 device forwards a Report message to the upstream device. The upstream can create or maintain the matching forwarding entry based on the Report message.
- When the last member of a multicast group leaves the group, the Layer 2 device forwards a Done message to the upstream device. The upstream device then deletes the matching forwarding entry.
An upstream Layer 3 device does not send Query messages as a querier when MLD is not enabled for some reasons, for example, the Layer 3 device has only static multicast groups. In this case, the wireless access controller cannot create or maintain group memberships even though MLD snooping is enabled. The MLD snooping proxy function enables the wireless access controller to send Query messages to downstream hosts. For the hosts, the wireless access controller is a querier.
Prerequisites
MLD snooping has been enabled globally using the mld-snooping enable command.
Configuration Impact
If MLD is enabled on the upstream Layer 3 device, enabling the MLD snooping proxy function on the wireless access controller may affect the querier election result. This is because the General Query messages sent by the wireless access controller may have a smaller source IP address than the General Query messages sent by the Layer 3 device. Therefore, MLD snooping proxy is not recommended on an MLD-capable multicast network.
Precautions
The configuration takes effect only after you run the mld-snooping enable command to enable MLD snooping in the VLAN.
After MLD snooping proxy is enabled in a VLAN, MLD snooping querier and MLD message suppression cannot be enabled in the VLAN.
If multicast VLAN replication is configured on the wireless access controller, the MLD snooping proxy function cannot be enabled in user VLANs.
