We have had an issue that causes every TV on the property to freeze from time to time and we thought we previously resolved it. We have 9 Meraki switches with 5 of them being MS390 and then MR30H access points with 1 port of the MR30H carrying the IPTV multicast VLAN. That port is connected to an IPTV in a hotel guest room. Our IPTV source is a 100 channel head end from COX. The problem first appeared when the MR30H AP's were updated from firmware 29.5.1 to 30.2 last June. We rolled back the AP's to 29.5.1 and the problem stopped. Then last month, a Meraki bot updated those AP's to 30.6 and the problem started again so we rolled back to 29.5.1 again. In troubleshooting, I realized that any time an MR30H is rebooted, every LG TV on the property freezes for about 1 minute and 30 seconds. A packet capture shows that every port on the TV VLAN starts flooding all 100 multicast channels which then overloads the port and TV causing the freeze. This only happens on our site with MS390 switches and MR30H AP's. We have multiple other sites with the same configuration except there are MS350 switches instead of MS390. We also have MR36 and MR56 AP's on this site. If I reboot those AP's, the network doesn't get flooded and the TV's don't freeze. So it seems the issue probably has to do with the built-in switch on the MR30H and the MS390 switch. Meraki support has not been able to figure out the problem and we left off with them talking about submitting a bug report for the MS390.
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