We are running CM 6.1.4 and enabled the network for MoH on multicast. The internal IP to IP phone is working on multicast MoH as shown by RTMT, however PSTN calls continue to show a Unicast MoH from RTMT.
We did verify network multicast functionality upto Voice gateway by enabling loopback interface with "ip igmp join <mcast address>" and ensuring show ip mroute displays incoming interface correctly as well as outgoing interface as loopback 0 interface.
The music is being played for PSTN receiver but RTMT still shows a unicast MoH resource active.
What is the reason for this? What configuration change, if at all, is needed to make MoH sent as multicast to PSTN on ISDN (on Voice gateway)