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Without IGMP Snooping, a managed switch treats a video stream from an IP camera the same as a broadcast – it sends a copy to every single port on the switch, even ports connected to devices that have no use for it. IGMP Snooping monitors which ports have subscribed to receive the stream and forwards it only to those.
In a surveillance network with 16 IP cameras all streaming simultaneously, the difference between flooding and targeted forwarding is significant in terms of network load and CPU overhead on connected devices.
- IGMP Snooping monitors join and leave messages sent by devices subscribing to multicast groups
- Only ports with active subscribers receive each multicast stream
- Reduces unnecessary traffic on ports connected to PLCs, access points, and management devices
- MLD Snooping is the IPv6 equivalent, supported alongside IGMP on modern industrial switches