Summary of IGMP Snooping Configuration Tasks

Configuring Basic IGMP Snooping Functions

When multicast data is forwarded to a Layer 2 multicast device connected to a user network segment, configure IGMP snooping on the Layer 2 multicast device to prevent multicast data from flooding in the broadcast domain and to accurately forward multicast data at Layer 2. After IGMP snooping is configured, the Layer 2 multicast device can listen to and analyze IGMP messages between multicast users and the upstream router. The Layer 2 multicast device sets up Layer 2 multicast forwarding entries to control multicast data forwarding. In this way, multicast data is not broadcast on the Layer 2 network.

Configuring IGMP Snooping Proxy

You can configure IGMP snooping proxy on a Layer 2 multicast device in either of the following situations:

• IGMP is not enabled on a Layer 3 multicast device (for example, static multicast groups are configured), and no IGMP querier is available on the network to maintain group membership. After IGMP snooping proxy is configured on a Layer 2 multicast device, the device functions as the IGMP querier to send Query messages to receiver hosts.
• IGMP is enabled on a Layer 3 multicast device. To reduce the number of IGMP Report/Leave messages transmitted between the Layer 3 multicast device and network segments of receiver hosts, configure IGMP snooping proxy on the Layer 2 multicast device between the Layer 3 multicast device and receiver hosts. The Layer 2 multicast device forwards IGMP Report or Leave messages from receiver hosts to the upstream device and sends Query messages from the upstream device to receiver hosts.

Configuring an IGMP Snooping Policy

To filter out multicast messages on a Layer 2 multicast device or limit the range of multicast groups that hosts can join, configure an IGMP snooping policy on the Layer 2 multicast device.

Configuring Membership Fast-Update

To improve running efficiency of multicast services and user experience, configure quick membership update on a Layer 2 multicast device so that the device quickly updates entries when receiver hosts join or leave a multicast group.

Configuring IGMP Snooping SSM Mapping

On a Layer 2 network, some receiver hosts can only run IGMPv1 or IGMPv2. To allow these hosts to use SSM, configure IGMP snooping SSM mapping on the Layer 2 multicast device.