On 18.06RC2, but consistent problem over various versions...
My network consists of three OpenWRT devices - 2xWNDR3700s used as dumb APs (as much disabled as possible) and an Asus RT-N56U used as a router (wifi disabled). 802.11R is enabled on the two APs and seamless roaming is working well. IGMP snooping is disabled on all the bridges.
WNDR3700#1 ))) ~~~ ((( Google cast devices
|----- RT-N56U ----- Modem ----- Internet
WNDR3700#2 ))) ~~~ ((( Google cast devices
The problem in having is that my five Google cast devices are not always discoverable. They work well temporarily if WiFi is restarted on the APs, but invariably over time some will cease being discoverable. Nothing seems to help.
Other things that rely on multicast DNS are working fine (Apple Time Machine springs to mind).
I might add that sometimes it will only detect the cast devices that are attached to the local router, but other times it will detect all of them. As snooping is turned off in the interface settings I can't see why this would be the case...
Any thoughts? I'm at my wit's end...