Multicast, IGMP snooping and Meraki MX

Hi guys,

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I have some questions concerning Meraki equipment and how the MX firewall handles multicast traffic:

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Example scenario: topology

1 x MX --> 3 x MS --> 5 x MR -> 5 IPTV STB Each MR AP has an IPTV STB connected.

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In this test scenario, the IPTV provider has 3 channels - Channel 1 (8 Mbps), Channel 2 (8 Mbps) and Channel 3 (4 Mbps).

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As IGMP snooping is available on MS Switches, each MR AP only gets the specific IPTV multicast stream, that the STB has requested. Happy network.

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The MX firewall, on the other hand, doesn't have IGMP snooping (I don't understand why...), so the MX floods all STB requested IPTV multicast traffic to every directly connected MS Switch, even the switches only connected to one MR AP / STB (see topology). Not so happy network.

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In our real life scenario, you have to increase IPTV provider channel nr. from 3 to 50 (3-400 Mbps total multicast traffic) and increase the amount of MS switches connected to the MX from 3 to 8, and you would have around a constant ~350Mpbs * 8 = 2.8 Gbps of multicast traffic being passed through the MX.

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This causes a lot of unnecessary congestion on the network backbone link between MX & MS.

I know that setting an aggregation switch between the MX firewall and MS switches, that has IGMP snooping would solve this issue, but that's besides the point.

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Would this amount of multicast traffic flooding negatively impact the MX performance, and if so, how much?

Thank you.