AV-over-IP deployments continue to scale in houses of worship, corporate campuses and regional sports venues, where multicast traffic from encoders such as Magewell Ultra Encode and NDI sources must share bandwidth with Dante and control data. The NETGEAR M4350 AV Line switch, positioned at the access layer in many of these racks, is frequently chosen for its 1 Gbps and 2.5 Gbps ports plus the AV-optimized web interface that pre-loads multicast settings.
IGMP snooping on the M4350 is enabled by default under the AV profile, yet field reports show that sources which never issue IGMP membership reports or which transmit constant group traffic regardless of receivers can keep all ports in the VLAN populated. This behavior leaves the switch forwarding streams to every downlink even when only one decoder is active, quickly consuming the 1 Gbps uplinks that many mid-size projects still rely on.
Installers who measured traffic on a recent 48-port M4350 stack found that a single misbehaving PTZ camera encoder was responsible for 280 Mbps of sustained multicast that never pruned. The resulting packet loss appeared only during live events, not during bench testing, because the camera only stopped sending when its HDMI input was removed.
Configuration Steps That Reduce On-Site Time
Technicians now add an explicit IGMP querier on the core VLAN interface and raise the query interval to four seconds to force faster leave messages. When sources still refuse to cooperate, they create static multicast groups tied to the known receiver ports and disable snooping on those specific VLANs. Both adjustments are saved to a custom config file that can be pushed via the M4350’s USB console before racks are closed up.
These extra steps add roughly 45 minutes per switch during commissioning and require a second technician with a laptop running multicast test streams. Labor budgets that assumed two days for a 12-switch AV network now carry a line item for “multicast validation,” pushing the total closer to the cost of upgrading a few links to 10 Gbps.
Forward-looking projects are therefore specifying switches with selectable IGMP proxy modes and per-port querier options rather than relying solely on snooping. Firmware updates from NETGEAR have begun to expose more granular timers, but integrators continue to test each new encoder firmware revision against the M4350 to avoid discovering the same flooding behavior after racks are flown.
One regional sports venue in the Midwest learned this lesson the hard way during a three-day tournament. After the M4350 stack was installed to support 22 NDI sources feeding a 12-screen video wall plus separate Dante audio, the production team noticed intermittent macro-blocking on two critical cameras. Packet captures revealed that IGMP leave messages from the wall processors were being ignored because the upstream encoder maintained an active membership report on every group, keeping all 48 ports in the forwarding state. Only after the integrator inserted a dedicated querier appliance on the core switch did the uplink utilization drop from 820 Mbps to 310 Mbps.
NETGEAR has acknowledged the limitation in recent knowledge-base articles, recommending that users enable “IGMP snooping querier” on at least one VLAN interface and set the maximum response time to one second. However, the same documents note that certain third-party encoders continue to transmit regardless of querier state, forcing users to fall back to static multicast filtering or port-based access lists. These workarounds are effective but erase the plug-and-play advantage originally marketed with the AV Line.
Looking ahead, several manufacturers are shipping switches that combine IGMP snooping with proxy and source-specific multicast filtering, allowing the network to drop unwanted streams at the edge without manual intervention. Until the M4350 receives comparable capabilities through firmware, integrators are budgeting extra commissioning hours and, in some cases, specifying 10 GbE uplinks as inexpensive insurance against multicast flooding that snooping alone cannot contain.
