igmp-snooping proxy (Bridge domain view)

Usage Scenario

Forwarding entries are set up based on IGMP messages exchanged between a Layer 3 device and user hosts. If there are many user hosts, redundant IGMP messages increase the workload of the Layer 2 device.

IGMP Snooping Proxy can address this problem. IGMP Snooping Proxy provides two functions: querier function and uniform Report/Leave message transmission function. The querier function enables an IGMP Snooping Proxy-enabled device to replace the connected upstream device to send IGMP Query messages. The uniform Report/Leave message transmission function enables an IGMP Snooping Proxy-enabled device to process IGMP Report/Leave messages received from downstream user hosts. Configuring IGMP Snooping Proxy on a device effectively saves bandwidth between the device and the connected upstream device, and reduces the load of the connected upstream device.

Configuration Impact

After IGMP Snooping Proxy is enabled on a device, Report messages sent by users will be terminated on the device.

Precautions

The following conditions must be met before the igmp-snooping proxy command is run:

• The querier function is configured on a device only after a static multicast group is configured on the connected upstream device. Otherwise, Report messages sent by user hosts cannot be forwarded to the upstream device. As a result, these user hosts cannot receive required multicast data.
• If the paths from a multicast source to user hosts are in the same Layer 2 network, the querier function can be enabled on a Layer 2 device. This does not affect the normal receiving of multicast data packets.