/mcp• Cisco Unified Communications Manager listens to multicast G.729 stream on external multicast IP and port value added with four that is configured on the MOH audio source configuration window. For example, if you configure an MOH audio Source with 239.1.1.1:16384, Cisco Unified Communications Manager listens to G.711 mu-law stream on 239.1.1.1:16384 and G.729 stream on 239.1.1.1:16388 (port value added with four). An MOH server cannot transcode for G.729 codecs. Callers who are using MOH G.729 codec require an external multicast RTP stream using G.729 or G.729a codec. Music On Hold Prerequisites • Before you configure multicast, ensure that you configure MOH server and audio sources. If you want to use fixed audio source, configure it before you configure multicast. • Make sure to decide whether you are going to do unicast or multicast Music On Hold • It is crucial to plan the capacity of the deployed and configured hardware and ensure that it can support the anticipated call volume of the network. You need to know the hardware capacity for MOH resources and consider the implications of multicast and unicast MOH in relation to this capacity. Ensure that network call volumes do not exceed these limits. When MOH sessions reach these limits, an additional load can result in poor MOH quality, erratic MOH operation, or loss of MOH functionality. • If you use multicast MOH and the devices that listen to multicast MOH streams are not in the same IP network, you must enable multicast routing in the IP network. Take care when you enable the multicast routing to avoid the potential flooding of parts of the network with wrongly sent multicast packets (specially, across WAN links). Disable multicasts on interfaces on which the multicast MOH packets are not required and use the Max Hops parameter. • For detailed information on planning your Music On Hold deployment, including server capacities, refer to the Music On Hold capacities topics in the Cisco Collaboration System Solution Reference Network Design. Music On Hold Configuration Task Flow Complete these tasks to configure Music On Hold (MOH) for your system. Procedure Purpose Command or Action Activate the Cisco IP Voice Media Streaming Service Application service to enable Music On Hold. Activate Cisco IP Voice Media Streaming, on page 621 Step 1 Configure basic server settings for the MOH server. Configure Music On Hold Server, on page 622 Step 2 Optional. Upload your own audio files to make them available as MOH audio streams. Upload Audio File for Music On Hold, on page 622 Step 3 Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs 620 Custom Features Music On Hold Prerequisites