@PhilipDAth wrote: It sounds like the switches were not processing multicast traffic correctly.  Are you running 10.x (like 10.43) code on the switches?   Also check out this excellent post on multicast configuration when you have more than one switch. https://community.meraki.com/t5/Switching/Multicast-Basic-s/m-p/25867#M2125 I read in to this, but I'm still unsure about this.   IGMP Snooping, allows us to send and recieve multicast streams out the same ports. If this is disabled, then we cannot recieve multicast streams stemming from ports where we send out multicast streams. Basically, depending on who comes first, whichever MX will not be able to reply on multicast streams.    Flood unknown multicast traffic; will allow the switches to flood multicast traffic out all ports. But is VRRP considered unknown multicast traffic? Or maybe multicast traffic with unknown source/destination, is just flooded out all switchports? ... View more