IGMP Snooping Application

Networking Description

As shown in Figure 9-5, multiple multicast sources such as Source1 and Source2 exist on a PIM network. The sources provide multicast video services for users on the LAN. Some users such as HostA and HostC on the LAN want to receive video data in multicast mode. To prevent multicast data from being broadcast on the LAN, configure IGMP snooping on Layer 2 multicast device to accurately forward multicast data on the Layer 2 network, which prevents bandwidth waste and network information leakage.

Figure 9-5 IGMP snooping networking

Deployed Features

You can deploy the following features to accurately forward multicast data on the network shown in Figure 9-5:

• PIM and IGMP on the Layer 3 multicast device Router to route multicast data to user segments.
• IGMP snooping on the Layer 2 device Switch so that Switch can set up and maintain a Layer 2 multicast forwarding table to forward multicast data to specified users.
• IGMP snooping SSM mapping on Switch when receiver hosts running IGMPv1 or IGMPv2 want to use SSM.

  Layer 2 SSM mapping must be combined with Layer 3 SSM mapping on the IGMP querier to ensure multicast data forwarding. You must configure Layer 3 SSM mapping entries on the IGMP querier.