MOH and Multicast Troubleshooting

bgibson · ‎10-16-2002

I am attempting to confiugure my MOH sources to be sent out via Multicast. They were unicast and they worked but I would like to move on to multicast.

Everything seems to be set up ok. I can see the mulitcast group being registered in the routers. However I can't seem to get any device to join to the IGMP group.

Does anyone know of a detailed white paper explaining how MOH process works? In particular I am trying to figure out how a PSTN gateway gets involved? Does Mulitcast MOH even work with a PSTN gateway?

Secondly is there information on the phone regarding MOH? If so what is it?

rchapee · ‎10-16-2002

What type of gateway are you using and what version of IOS? What CCM version are you using??

The first time I tried this I was using 3600's and 2600's for GW's running 12.2.11T which I know supports multicast MOH. If using a T1 it must be a PRI or if it is CAS it must be E&M. My CCM version is 3.2.2cSPe.

There is one big thing that took some time to figure out in the lab that I will pass on. The company was using EIGRP and had a frame-relay network. Well multicast is a broadcast and shares the same bucket as any routing protocol. My routes would keep going up and down every 30 seconds because the multicast would overwelm the buffer. You must increase the broadcast buffer on the frame-relay interface.

I will post the router config on www.iptnetworkers.com tomorrow if you want to see it.

** www.iptnetworkers.com ** small but growing fast!

bgibson · ‎10-17-2002

The gateway is a 3640 running 12.2.12(11)t code with a PRI. I am truly baffled.

The problem is that phones on the same network as the gateway receive the MOH. But the gateway doesn't.

IF a person calls in through this gateway to an IP Phone and is put on hold does the IP Phone relay the MOH multicast or does the gateway pick up the signal directly? I assume the latter but I would like to make sure.

dweiner · ‎10-17-2002

Do you have the global command "ccm-manager music-on-hold " in your config? This is required whether mgcp or h.323

rchapee · ‎10-17-2002

Is this a H323 GW...I did not think Multicast MOH is supported on an H323 gateway.

make sure you have a MOH source defined on your gateway or are using a device pool that has one. What version of CCM

BTW - I am still going to post screenshots and configs on IPTnetworkers I just have not had time to do it and document properly. Sorry

** http://www.iptnetworkers.com **

dweiner · ‎10-17-2002

MMoH is supported with both H323 and MGCP

gillins · ‎10-20-2002

I have a few ideas for you.

1. if there are any routers in between your callmanager servers make sure you have turrned on multicast routing.

it only takes a few simple commands

global:

ip multicast-routing

then on the interfaces that the multicast would pass through

ip pim sparse-dense-mode

2. make sure the audio source and the moh server is set for multicast.

3. if all of the above is set up then on the moh server setting make sure the hop count is greater or equal then the router hop count from the server to the source.

To see if the audio source is getting to the remote router do a "sh ip pim rp" on results you should see a line with the multicast address of the one set up on the callmanager and you should see the actual ip address of the callmanager.

hope this helps

scott