Internet Group Management Protocol snooping

Internet Group Management Protocol (IGMP) snooping is an activity performed by switches to track the IGMP communications related packet exchanges and adapt to filtering the multicast packets. The system uses IGMP Version 3 and supports up to 3000 multicast streams.

IGMP is a communications protocol that enables a node (receiver) to inform a multicast router about the node's intention to receive particular multicast traffic. IGMP runs between a router and a node that enables the following actions:

Routers ask nodes if they need a particular multicast stream (IGMP query)
Nodes respond to the router if they are seeing a particular multicast stream (IGMP reports)

Switches featuring IGMP snooping produce useful information by observing the IGMP transactions between the nodes and routers. The IGMP snooping function enables the switches to correctly forward the multicast packets, when necessary, to the next switch in the network path.

Switches monitor the IGMP traffic, sending out only multicast packets when necessary. A switch typically builds an IGMP snooping table that has a list of all the ports that requested a particular multicast group. The IGMP snooping table is used to allow multicast packets to travel across the network or to disallow them from traveling across the network. IGMP snooping is enabled by default on all IP Group VLANs. However, you can configure your switch to disable IGMP snooping through the console or by using the system management Networks REST API. The preferred configuration is to enable IGMP snooping.

Note: IGMP snooping is available as a global setting for ToR switches. It can be enabled or disabled any time.

The IGMP communication protocol is used by the nodes and the adjacent routers on IP networks to interact and to establish ground rules for multicast communication and establish multicast group membership.