Multicasting MoH

[arrrghhh3]

So I have several problems, but I'd like to start with this seemingly *simple* one. We're running CUCM 7.1.2, and I think multicasting MoH is configured correctly, I even see the MOHMulticastResourceActive value changing in the RTMT Performance section.

The problem is, when I set the multicast stream to be the first priority in CUCM, I hear no hold music. When I set our unicast stream to be first priority, I hear music. So this tells me we're only unicasting. How do I setup multicasting? Is there a good step-by-step guide? Based on conversations with our network administrator, multicasting is enabled on our LAN at the very least. He is not seeing any multicast packets coming out of CUCM, so I'm pretty certain something is mis-configured. Since I thought it was all correct and I was simply hearing silence, I assumed our switches/routers were blocking the traffic, but not according to the admin.

So any help would be greatly appreciated. We have a much larger problem with remote sites, SRST, using the gateways to stream MoH, but I'd like to sort out why we can't even multicast from CUCM to the local network. Thanks!!

[robert49729]

FYI > We've seen this before "hear dead air" on multicast from the CUCM when you haven't uploaded the music file to each server on the cluster (uploaded to each individual MOH server) - Unlike CM 4.x where media service references a shared folder.

Maybe that will help at your corp site?

Just ideas =)

[James Hawkins]

Guys,

SRST only supports streaming of MoH using the G.711 codec.

http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00802d1c31.html#wp1043334

If you are talking across the WAN and using G.729 and your call is put on hold and receives MoH from the local gateway the codec used will swap and then swap back when the call is taken off hold.

You can see this by pressing the help button twice when on a call using a 794x/796x/797x phone.

The file that is streamed from the SRST router also needs to be in the correct format - see extract from earlier link.

The flash memory in each of the Cisco SRST gateways must have an MOH audio file. The MOH file can be in .wav or .au file format, but must contain 8-bit 8-kHz data, such as an a-law or mu-law data format. A known working MOH audio file (music-on-hold.au) is included in the program .zip files that can be downloaded from http://www.cisco.com/pcgi-bin/tablebuild.pl/ip-key. Or the music-on-hold.au file can be downloaded from http://www.cisco.com/pcgi-bin/tablebuild.pl/ip-iostsp and copied to the flash memory on your Cisco SRST router. Another option is copying one of the MOH files, such as SampleAudioSource.ULAW.wav, from C:\Program Files\Cisco\MOH on Cisco CallManager.

[arrrghhh3]

Yes, and I thought I made most of that clear already...

Either way, I know it's *supposed* to be G.711, but it wasn't - turns out the MoH file that everyone claimed was working just fine, is 16-bit stereo. As you've stated, it needs to be 8-bit mono. I assumed the people who designed this used a proper file, but that's what I get for assuming. Turns out our config everywhere was setup correctly, but that file was incorrect. I probably should've just tried the default file instead of trusting that "it was working properly before..."

Either way, my problem is solved, thanks for all the helpful responses! And jamesha - most of your statement is correct, but you have to be using CUCM 4.x or older for that last line to be applicable!