CUCM Transfers external number is not working

[Yannick Vranckx]

Dear,

I have this strange issue on a CUCM 8.6 with a CUBE connected. So a caller calls the reception and the reception picks up the phone. The reception wants to do a guided transfers, so he rings the co-worker and announces the transfer. He presses the transfer button and the call is fast busy before there anyone heard.

I've enabled MTP on the SIP trunk to the CUBE and then there is no problem whatsoever, i also hear the Cisco music. But this is a multisite environment and other sites don't have this issue with MTP also disabled. There's one difference, the site impacted has a different ITSP provider.

I've attached the debug ccsip from the CUBE and tried to put above the log the steps the CUBE does, but at the end there are alot of ACKS & OK's that i don't understand.

IP's to understand: 10.3.26.10 / 10.3.26.11 CUCM, CUBE's interface to CUCM is 10.90.49.10, Provider is 195.22.64.67

I will attach the debug ccsip file, please use discretion ofcourse.

Kind Regards,

[dino55088]

Does the outside caller hear MoH? I can see MoH send in trace..

When does the call fail ... when the internal transferor wishes to transfer after speaking with the transfer-to party?

Can you do supervised transfer for  internal calls ?

Do you have CUCM trace? You can see a BYE coming into CUBE from CUCM and not sure why this happens. Wonder which location transfer-to party is located- maybe codec/region related?

[Manish Prasad]

Hi Yannick,

If you don't want to utilize MTP then you have to keep uniform codec throughout the call. What happening in your current setup is the first inbound call setup using G711 codec and when receptionist put caller on hold then CUCM uses G729 codec for MOH media , this is why caller is not able to hear music when put on hold (due to lack of media resource) .

When CUCM sends Re-Invite to retrieve the call from MOH at that time ITSP send only G711ulaw codec and call gets disconnected due to mismatch of codec (cause code - 65).

There are two ways to go...

1. Change the service parameter of Cisco IP voice media app and select 711 ulaw as supported moh codec.

2. Contact you SIP service provider and show them SIP logs and ask them to support g729 codec aswell.

Thanks

Manish

[Yannick Vranckx]

Ok,

So the call fails from the moment the receptionist presses transfer to transfer the call.

The other party doesn't even hear their phone ring. So call comes in, receptionist picks up. Does a directed transfer to a co-worker, so calls the co-worker and announces the transfer and then presses transfer and the call is straight gone.

With MTP it does work so that would indeed explain i'm having a codec issue. What i don't understand is that the call would drop? The incoming call should be G711, the call manager accepts G711 without MTP on the CUBE correct? During the transfer moment the MoH sends the music with G729? Or does the CUBE send the call to CUCM with G729? 

The ITSP will not support G729, they aren't that cooperative, would it work to put the MoH local on the CUBE? Is MoH then the main issue in this transfer?, or just remove the Music on Hold for the entire site.

Thanks already for the help

[Manish Prasad]

So the call fails from the moment the receptionist presses transfer to transfer the call. - Yes

What I don't understand is that the call would drop?- Due to unsupportive codec from ITSP side.

The incoming call should be G711, the call manager accepts G711 without MTP on the CUBE correct? - Yes that's correct.

During the transfer moment the MoH sends the music with G729 - Yes.

Or does the CUBE send the call to CUCM with G729? - Its CUCM which inserts the MOH.

, would it work to put the MoH local on the CUBE? Is MoH then the main issue in this transfer?, or just remove the Music on Hold for the entire site -The problem is not with the MOH file or its location , the actual problem is with the codec which is being used at the time of call hold and retrieval.

Change the service parameter which I recommend earlier or use media resource to get this transfer work.

 There are many post from Ayodeji on this forums explaining SIP call transfer message flow , I would recommend have a look at the posts.

Thanks

Manish

[Yannick Vranckx]

Sorry if i sound stupid:

But couldn't the CUBE do this transcoding? 

Because we are connecting to a CUBE, but i think it is still missing some vital configuration.

[Manish Prasad]

To answer your question i need SIP logs from CUBE with MTP enabled on SIP trunk.

[Yannick Vranckx]

a normal "debug ccsip messages" i presume

I will get this later today