MOH using Multicast does not work over PSTN

Unanswered Question
Oct 17th, 2007

MOH works between IP phones but not between an IP phone and a PSTN phone. When put on hold holdee gets silence.

Loopback interface on the two MGCP Voice Gateways are not configured, but we have been adviced to put a loopback interface with a routable IP address on it to fix this problem. These routers each has a BVI40 interface which is in the same VLAN 40 as the CCM and we can confirm that the Multicast MOH stream is hitting the Voice Gateway.

These two Voice Gateways connect to CAT 6500 interfaces which are in VLAN40 same as the CCM.



We have the

ccm-manager music-on-hold

command and this is where my question is.

Do we have to have the command

ccm-manager music-on-hold bind interface BVI40 command ?

We are using CCM version 4.1 and it is configured to send MOH Multicast and increment on Port Nummber rather than on IP address for the various codecs.

I have read all of the information at all of the links below and I can't still seem to find an answer. But the links are very informative in understanding MOH and MOH using Unicast and Multicast.

I have this problem too.
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thisisshanky Wed, 10/17/2007 - 21:11

May I ask why you have a BVI interface on a router ? Are you using bridging. What router are you using ?

ccm-manager music-on-hold binding to a particular interface is not absolutely required.

astanislaus Wed, 10/17/2007 - 21:42

Yes they are using bridging. When do we need the bind MOH to teh interface?

astanislaus Thu, 10/18/2007 - 16:12

After adding

ccm-manager music-on-hold bind interface BVI40


it MOH from IP Phone to PSTN Phone works fine.


To answer your question - The two MGCP Voice Gateways (R1 and R2) are Cisco 3845 with Gi0/0 and Gi0/1 in bridge-group 40 with BVI40 interface having the IP address. Configuration similar on R1 and R2 . Then R1's Gi0/0 and R2's Gi0/0 connect to one CORE1 (CAT 6500) and R1's Gi0/1 and R2's Gi0/1 is connected to CORE2 (CAT 6500). This is how the routers are setup. I am unable to answer your question on why they did it this way rather than have Gi0/0 and Gi0/1 in different IP subnets and run OSPF or simpler still just run HSRP. if redundancy is what they are trying to achieve and to achieve they say they are using BVI interface.

astanislaus Thu, 10/18/2007 - 16:14


Please explain on what circumstance ccm-manager music-on-hold bind interface is required. In our case it was required. But you said that the bind interface is not always required. So when is it required and when is it not required. May be it is not required if a loopback interface was also defined on the router.

arlincurtis Thu, 10/18/2007 - 17:48

I'm guessing you're using MGCP gateways?

We had to use the mgcp bind command to fix a similar issue, except it was no moh over an ICT. Otherwise your gateway registers with the external serial IP rather than something from your internal subnet. Once we did that and made sure all the media resources were in place, MTP, transcoding etc we were good to go. Try the config below, which is what we have.

ccm-manager redundant-host (IP address)

ccm-manager mgcp

ccm-manager music-on-hold

ccm-manager config server (IP address)

ccm-manager config

mgcp bind control source-interface Loopback0

mgcp bind media source-interface Loopback0


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