The term Multicast can apply to both IP Multicast and the KNX point-to-multi-point, connection-less (multicast) Transport Layer communication mode.
In the case of IP Multicast, the KNXnet/IP driver does support it in order to facilitate Device Discovery on the network.
NOTE: The default IP Multicast Address is 224.0.23.12..
With regard to the KNX point-to-multi-point, connection-less (multicast) Transport Layer communication mode, the KNXnet/IP driver inherently supports this communication mode in so far as it makes use of the A_GroupValue_Read-PDU, A_GroupValue_Response-PDU and A_GroupValue_Write-PDU Application Layer services which are only supported using this communication mode.