Summary of IGMP Configuration Tasks

To configure receiver hosts to join a multicast network and receive multicast data, you must configure basic IGMP functions on the switch interfaces connected to the receiver hosts.

With basic IGMP functions configured, a multicast switch can exchange IGMP messages with receiver hosts using default settings. You can optimize IGMP performance on the switch according to network security and performance requirements.

The source-specific multicast (SSM) model allows IGMPv3 hosts to specify the multicast sources from which they want to receive data. To allow receiver hosts running IGMPv1 or IGMPv2 to use the SSM service, configure IGMP SSM mapping on the multicast switch.

You can configure an IGMP limit on the multicast switch to limit the number of group memberships on an interface or in the system. This improves network stability and performance. Without an IGMP limit, the number of groups and group members is unlimited, and can therefore cause performance degradation on a multicast switch.

In a simple tree topology, the multicast device directly connected to a user network segment does not need to run complex multicast routing protocols such as PIM. However, if the multicast device transparently forwards IGMP messages, the upstream access device must manage a large number of users. In this case, configure the IGMP proxy function on the multicast device to enable the router to collect IGMP Report and Leave messages from receiver hosts before sending these messages to the upstream access device. In addition, the router maintains membership and forwards multicast messages based on the membership. To the upstream access device, the multicast device is a host.