Multicast MoH does not work for PSTN callers in Cisco CallManager 4.x

[TCC_2]

Core Issue

Multicast Music on Hold (MoH) does not work for Public Switched Telephone Network (PSTN) callers. IP phone-to-IP phone multicast MoH works fine.The most likely reason for this issue is that the gateway is not configured for multicast.

Resolution

: Issue this commands on the gateway under the global configuration mode in order to resolve this problem:

ip multicast-routing

Apply one of these commands for all interfaces where multicast packets traverse:

• ip pim sparse-mode
  
• ip pim dense-mode

Note: These commands not only enable multicast routing, but also allow the router to decode the packets so that it can send the audio out.

Some other things to check:

• Verify that the gateway is in a device pool that has multicast MoH enabled. In other words, the device pool is configured with the correct Media Resource Group or Media Resource Group List.
  
  
• Verify that all devices use the same codec.
  
  
• Verify what codec the call comes from and the PSTN uses when it connects to the IP phone. If the PSTN calls come in with a codec other than G711, MoH must be configured to support all of the other codecs. In order to choose the codecs, complete these steps:
  
  
  1. Open the Cisco CallManager admin page.
     
     
  2. Choose CCMAdminpage > Service > Service Parameters > (Choose Publisher) > Cisco Ip VoiceMedia Streaming Application.
     
     
  3. Scroll to the bottom and highlight all of the available codecs.
     
     
  4. Click Update.
     
     
  5. Choose >CCMAdminpage > Application > Serviceability > Tools > Control Center.
     
     
  6. Restart the Cisco IP Voice Media Streaming application on the publisher and all the subscribers.

Refer to Music on Hold for Cisco CallManager 4.x and Music on Hold for Cisco CallManager 4.2(x).

Note: Cisco CallManager 4.2(x) uses common profiles in order to control the Music on Hold for a large group of users. Create a new common profile and use the Bulk Administration Tool (BAT) in order to assign this profile to all of their IP phones. Refer to Common Profile Configuration for more information.

Problem Type

Call control software  (CallManager, CallManager Express, ICS7750, SRST, SS7 call agents)

Call Control

CallManager

CallManager Features

Music on hold (MoH)

Failure Type

Cannot start, stop, schedule, reset, power up, power down, run, initialize, open, close, activate, deactivate or load

End Where Problem is Heard or Device Type Involved

PSTN/PBX or voice gateway connected device

CallManager Versions

CallManager 4.x

Music on Hold (MoH)

Multicast MoH