Overview IGMP snooping

IGMP Snooping (Internet Group Management Protocol snooping) is the function designed for the device that does not support IGMP to reduce the spreading range of the multicast service packet and prevent the multicast packet from being spread to the network segments that do not need the multicast packet. It forms and maintains the downstream member port list of each multicast group at the local by listening to IGMP packets. In this way, when receiving multicast service packet, forward at the specified downstream member port. Meanwhile, IGMP Snooping can listen to the IGMP protocol packets and cooperate with the upstream multicast router to manage and control multicast services.

IGMP Snooping mainly realizes the following functions:

• Listen to the IGMP packets to set up multicast information. IGMP Snooping gets the downstream multicast receiver information by listening to IGMP packets, realizing the forwarding of multicast service packets at the specified member port.

Listen to the IGMP protocol packets. In this way, the upstream multicast router can correctly maintain IGMP member relation table.