David, Thanks for the continued input. I ended up placing multicast routing global and on the interface, but the scenario remained. I placed the IP phones on the same 3560 switch as CUCM, same problem. If I sniff the phone's port, I do see source IP address=CUCM_MOH, Dest IP address going to 239.1.1.1  source/dest UDP 16384, but just hear ToH on the phone on hold. Is ToH Multicasted? I wouldn't think that a CUCM cluster would attempt to put out a ToH and an MoH stream to the same phone. It certainly seems as though the multicast stream is getting to the phone. I also think the file is valid, because if I uncheck multicast (and only have that one MOH server in the MRG), I do receive music.

Any thoughts?

Thanks!

Tone on hold shouldn't (I don't think) be multicasted.  Sounds like there is something amiss somewhere in regards to the phone's switchport actually joining the mcast group.  Can you scrub your config and then post it (i.e., switch and router configs for multicast)? I, admittedly, may be barking up the wrong tree but from the CUCM perspective - once you set the multicast MoH source then there's not much else to it.  Most issues after that are typically network-related so I'd like to make sure we're all square there first.

Hailey

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Hi

Hailey is correct; ToH is signaled out via SCCP and generated locally on the phone.

If you get ToH, it means that CCM has told the phone to play out ToH.

If (for example) the phone was configured to receive Mcast MoH, but could not, you would get complete silence, as the CCM isn't aware of whether or not the phone actually picks up the RTP that CCM is sending out. This is how the 'trick' of streaming MoH from a local gateway works...

I would suggest that you have a misconfig on CCM that is causing an invalid stream to be selected - e.g.

- you haven't uploaded the MoH files to ALL your servers

- you have set an invalid source on the device that is instigating the hold (not the phone being put on hold)

- you have an MRGL assigned to this phone that does not include the MoH servers

- you have a regions setup that does not permit the codecs being used by the moh servers to the phone (g711 by default)

Regards

Aaron

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To add to Aaron excellent post, you also need to enable multicast on the MOH file itself.

Good follow-up, Aaron. All definitely valid points.

Thanks guys for all the input. The ToH information is key. I guess I never thought about where the ToH was generated from, and knowing it comes from the phone is most helpful.

RTMT does show a MoH "no more resources available" error message. The MoH server is registered and is part of the MRG, within the device's MRGL.

I am using the default MoH source file "SampleAudioSource" source file #1. They are present on both servers. I have the MoH server and phone within the same location/region. If I uncheck "allow multicast", the same file works fine as uni-cast. The other odd thing, is that when I check multicast Moh (in the source file, MoH Server and MRG) I do see multicast dest IP 239.1.1.1 UDP port 16384 go to the phone, but the phone plays ToH. This happens whether I try to stream MoH from my Pub or Sub. I wish I had a method to listen to that multicast stream to see if it is audible, or whether the phone receives it but can't play it, therefore playing ToH.....I guess I also need to see the phone config.xml file being loaded after I set the MoH to multicast, to see if the phone is being told the correct Multicast/MoH information. Any other ideas?

Thanks again for all the input.

Hi

You can do a packet capture using wireshark ; this will allow you to decode the SCCP and see what CCM tells the phone to listen to. If you get ToH you'll just see a 'StartTone' message.

You should also be able to squirt out the RTP file using the RTP Analysis function in Wireshark. You usually have to first right click the UDP packet and tell it to 'Decode as..' RTP.

I would leave the MoH sources, and servers mcast enabled permanently, and just use the toggle on the MRG. I would normally create a UCAST_MOH and MCAST_MOH, and then have two separate MRGLs (ucast/mcast) each containing the appropriate MOH MRG along with your other things. You can then switch between the MRGLs to turn it on/off.

There's always the chance when making lots of changes that you aren't resetting all that needs to be reset.

Get it so you can see the MoH, and then concentrate on why CCM is telling the phone to play out ToH. And be aware that just because your phone can see the traffic doesn't mean it's necessarily asked to see it - if you wireshark the port when the phone is idle you may still see it (LAN config dependant).

Regards

Aaron