MLD Snooping-enabled Queriers and Non-queriers

An MLD snooping-enabled device can be configured as a querier (active) or non-querier (passive). An MLD querier sends queries; a non-querier listens for MLD queries and forwards them to the entire VLAN. When multiple MLD snooping devices are connected together, and there is no connection to an IPv6 PIM-enabled port, one of the devices should be configured as a querier. If multiple devices are configured as queriers, after multiple devices exchange queries, then all devices except the winner (the device with the lowest address) stop sending queries. Although the system works when multiple devices are configured as queriers, Ruckus recommends that only one device, preferably the one with the traffic source, is configured as the querier.

VLANs can also be independently configured as queriers or non-queriers. If a VLAN has a connection to an IPv6 PIM-enabled port on another router, the VLAN should be configured as a non-querier.

Because non-queriers always forward multicast data traffic and MLD messages to router ports which receive MLD queries or IPv6 PIM hellos, Ruckus recommends that you configure the devices with the data traffic source (server) as queriers. If a server is attached to a non-querier, the non-querier always forwards traffic to the querier regardless of whether or not there are clients on the querier.

Note: In a topology with one or more connected devices, at least one device must be running PIM, or configured as active. Otherwise, no devices can send queries, and traffic cannot be forwarded to clients.

To configure the MLD mode (querier or non-querier) on an MLD snooping-enabled device, refer to Configuring the MLD Snooping Mode and Version Globally. To configure the MLD mode on a VLAN, refer to Configuring MLD Snooping Options for a VLAN.