Multicast MOH from Branch Router Flash Configuration

All IP Phones must be able to access the main-site CUCM MOH server from their media resource group list.
Use Multicast for MOH Audio check box has to be checked at the media resource group that includes the multicast-enabled MOH server.
G.711 codec is used between the MOH server and the branch phones, because SRST multicast MOH supports only G.711.
Recommended practice dictates that you increment multicast on IP address instead of port number.

1. Enable multicast routing in the network.
 (config)#ip multicast-routing
 (config-if)#ip pim sparse-dense-mode
2. Configure multicast MOH in CUCM:
 a. Configure MOH audio sources for multicast MOH.
 b. Configure MOH audio server for multicast MOH.
 c. Configure the maximum hop value to prevent multicast MOH streams from being sent over the IP WAN.
3. Enable multicast MOH from branch router flash at the branch router.
call-manager-fallback
 ip source-address
 moh moh-file.au
 multicast moh 239.0.0.1 port 20120
4. Optional: Use alternative methods to prevent multicast MOH streams from being sent over the IP WAN:
 a. Use IP ACL at the IP WAN router interface.
 b. Disable multicast routing on the IP WAN router interface.