Understanding MOH configuration

[wilson_1234_2]

We currently have a CUCM cluster of three servers running version 7. We are utilizing a SIP implementation with the HQ site as the hub, all calls go through the main site, then to the branches.

I am trying to get an understanding of how our MOH is configured and works and would appreciate some assistance.

Currently we have in Call Manager

Media Resources, the MOH server Audio Source has two items.

Stream 1 and Stream 26. Both of these are configured the same way, with the same audio source file, Play Continuously and Allow Multicasting checked.

Fixed MOH Audio Source Configuration

One entry is enabled, but Allow Multicasting is not checked.

MOH server

Shows the three Call Manager servers, shows the selected Audio Sources, Multicast is not checked.

In each branch h323 voice gateway, we have the wav file loaded in flash.

It is unclear to me what all is making the MOH function when an offnet caller calls in and hears the MOH file.

Is the call manager config only to determine where the end user gets the wav file, and once the end user is on hold, the gateway plays the wav file? Or is the wav file located on the call manager servers and end user hears file played from server?

The latter makes much more sense, but how can I confirm? Also, where does the inbound caller get the config to allow MOH?

[Jonathan Schulenberg]

If Enable Multicast is not checked on any of the CUCM MoH Servers' configuration then all MoH streams will be unicast. Which CUCM node is chosen will be determined by the held party's MRGL. The stream chosen (1 or 26) will be chosen based on the holding party's Network/User MoH Stream. This occures at a Global, Common Device Configuration, Device, or DN in increasing specificity.

The router-based file is only used when multicast is use and there is a WAN link without multicast support between the CUCM node running IPVMSA and the gateway/phone.

[wilson_1234_2]

Ok, Thanks. Looking at the config again, I see there is a Multicast server configured, Two do not have Multicast enabled and one does.

Please bear with me as I try and trace what is happening here.

When you say the "helds" party's MRGL, how do I determine that for an offnet caller?

For example, when an outside caller calls in, the called number is translated to a four digit number on the SIP gateway, then sent to call manager, where it is a four digit directory number.

When looking at the four digit number, I see no MRGL configured, and nothing for User Hold MOH Audio Source, or Network Hold MOH Audio Source.

[Marwan ALshawi]

There are two places where you can assign the MRGL

Device pool level

And the phone level

If both configured then the phone level one will take precedence

Same thing for the gateway settings in CUCM

Hope this help

[wilson_1234_2]

Ok, I appreciate your reples.

It looks like the MRGL is where we are grabbing the MOH file from.

It looks like the offnet caller would be getting the MOH config from the MRGL configured on the device pool the SIP trunks are in?

Here is what we are experiencing:

after changing the MOH file, whenever an inbound call comes in, we get MOH about 25% of the time.

We have HQ and DR CUBE routers and inbound calls are RR to those two gateways. Both gatewasys are experiencing the same thing.

We have tried everything in the general troubleshooting tips, but nothing has changed but the file itself

- Ensure that media resource is enabled. Media Resource->MoH Server and verify that the run flag is set to YES.

- Restart the Cisco IP Voice Media Stream App service.

- Check if G711,G729 is enabled for MoH in Service Parameters->Call Manager->Cisco IP Voice Media Stream App service.

- Make sure that the IP Phones or Gateways has assigned the MRGL that include the MOH resource.

A couple of things I still don't see,

in the config, we tell Call Manager the MOH audio source, the MOH server, but I do not see where the MOH server knows where the file is actually located.

For example, for each branch, the file is located on the local voice gateway, for the HQ and DR sites, the file is located on the local Call Manager server itself.

How does Call Manager know to pick up the MOH file for the branch when supplying MOH for that branch?

And, (maybe this is too obvious) does Call Manager use the locally configured MOH server for the source of the audio (wav file)?

[Chester Rieman]

This is useful for MMOH with CUBE:

http://www.cisco.com/c/en/us/support/docs/unified-communications/unified-border-element/116392-technote-product-00.html

[Marwan ALshawi]

Just to add to the above post from Jonathan

When the multicast Moh enabled on the MRG and Moh source the phone will send igmp join to the configured multicast group to join this Moh stream and the trick here is to configure the multicast hops as max of one hope and configure the voice gateway located locally to use the same ip for multicast in this case the voice gateway will reply to the igmp request for multicast streaming

See the bellow helpful link for more derails about it's config

http://ccieash.wordpress.com/2010/06/29/moh-issues-and-resolution/

Hope this help

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