MoH Multicast Using Local Loopback

Unanswered Question
Aug 3rd, 2010


Where do I start, this little issue has been giving me a headache!

We have a requirement for phone calls internal to internal to stream Music on Hold from the Local Flash.

We have -

1 x 2811 Router, with Multicast Routing enabled and ip pim sparse mode on loopback 0 and interface FastEthernet 0/1

1 x 3750 L3 Switch , with Multicast Routing enabled and ip pim sparse mode on VLAN facing Router and VLAN that has phones. (SVI's on switch)

For basic testing i wanted to see if Multicast works on the LAN with nothing configured, so we had one PC in one VLAN sending to (TTL = 1) and a PC is another VLAN listening on and it works across layer 3 switch.

So my problem, am I configuring multicast correctly?

My traffic flow I believe is Phone listens to, switch has this in its mroute table, forwards request to router, router starts sending MoH to

Has anyone been able to get this working? Hopefully this is understandable, I only just started to understand Multicasting.

Any imput would be appreciated.



I have this problem too.
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mikeduffy13 Mon, 08/09/2010 - 07:05

On  your router, make sure that you hav:

mgcp bind control source-interface FastEthernet0/1 (or SVI)
mgcp bind media source-interface FastEthernet0/1 (or SVI)

mikeduffy13 Mon, 08/09/2010 - 07:09

Also make sure you have this configured under call-manager-fallback (if an srst router)

moh Sample.wav (or whatever your local flash audio source is)
multicast moh [multicast origination ip] port 16384 route [default gateway ip] [loopback ip]


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