Neil is right, controller will send with the highest mandatory data rate.
If you have set 6M,9M, 11M, and ,24 as mandatory rates, the controller will send multicast packets at 24M only.when you set 9M to mandatory and the higher rates to supported, the controller will send multicast packets at 9M.
Check the need of your network/environment. To attain the multicast rate in the entire cell , It is good it keep it on 9M to be the mandatory rate, This will make the cell size a bit smaller. By doing this you can also prevent the network from B only clients.
Ruckus SmartCast processes multicast at lowest configured data rates, default 1mb
in 2.4G, 2mb in 5G. As Neil implies, configure your WLAN with WPA2/AES combo
(not auto), and you can configure a couple WLAN commands thru your ZoneDirector
CLI configure mode. Ofdm-only, will set the bss-minrate to 6mb. We have a built
in Multicast-to-Unicast conversion, called Directed Multicast, which will attempt to
send the first 5 group members their traffic via TCP over UDP. You may wish to
experiment with DM enabled and disabled, and with bss-minrate of 6 or 12mb.
(by default sets bss-minrate to 6mb)
no qos directed-multicast
qos directed-threshold 0
I suggest to test with these settings first, and you may increase the bss-minrate
if you are near enough to get good throughput.
If you do not specify OFDM-only, you may have CCK clients who only communicate
at 1, 2, 5.5, 11mb, and should try bss-minrate 5.5 or 11. With OFDM-only, you can
set bss-minrate to 6mb, 12mb, 18mb (but I wouldn't go higher unless you're close).