How to send multicast message to devices on ChirpStack v4

[QinLimin]

Hi Guys,

I had deployed chirpstack v4 and send unicast message successfully, but multicast functions on v4 still failed, I have the following question need to be clarified.
1, Will chirpstack send McGroupSetupReq MAC command to each device when I add the devices to a such multicast group? Or need to send McGroupSetupReq MAC command manually?
2, How the chirpstack to calculate the payload of McGroupSetupReq message when MAC command sending?
3, Do I need to configure any parameters related to multicast in the device？

Appreciate very much if someone can help?
Thanks!

[brocaar]

@QinLimin

1, Will chirpstack send McGroupSetupReq MAC command to each device when I add the devices to a such multicast group?

It does not. When you add devices to a multicast-group, you must configure these devices out-of-band with the multicast configuration, or send the McGroupSetupReq yourself (you can enqueue this command as normal unicast downlink).

[QinLimin]

Thank you Brocaar, multicast worked after we send McGroupSetupReq MAC command via port 200.