Internet Group Management Protocol (IGMP) snooping is the process of listening in to IGMP network traffic. IGMP snooping can significantly reduce traffic in cases of media streaming and other bandwidth-intensive IP multicast applications. With IGMP snooping, devices can make intelligent multicast forwarding decisions by reducing network capacity requirements.
When is it necessary to enable IGMP snooping?
Example:
Imagine a network that has an AP and several CPEs. An IPTV service is being provided to the clients. When a client decides to watch IPTV, the multicast traffic carrying TV data travels to the subscriber as well as to the rest of the CPEs connected to the AP. Such multicast flooding will reduce network bandwidth for the clients behind other CPEs. To avoid flooding the entire network, enable IGMP snooping on the AP (under Configuration > Network). Once the setting is enabled, multicast data will be sent to the specific subscribers only.