CUCM 6.1 SIP Trunk MTP not being used?

Unanswered Question
Feb 6th, 2008
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Hi,


We have a CCM 4.3 with a sip trunk going to our provider. The traffic is passing our firewall where it is being natted.

This configuration is working fine.

We are now planning to migrate to CUCM 6.1. When placing an inbound call via the SIP trunk to the CUCM 6.1 , the caller keeps getting ring tone even when the ipphone has picked up the call.

Checking the FW logs reveals that the voice packet is being dropped because of an illegal sip redirect from the CUCM to the IP of the ipphone.

So I'm guessing the MTP is not being used in the SIP trunk for some reason.


Any ideas?


Thanks,


Jeroen

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jeroenhermans Tue, 02/12/2008 - 23:44
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Hi,


Thanks for your reply.

The sip trunk is currently configured with "Media Termination Point Required" enabled.

I also added a media resource group list with only the MTP inside and added this to the config of the trunk.

MTP Preferred originating codec is set to 711Alaw.

I don't have the traces. I will enable them now and make some testcalls.


Rgds,


Jeoren

noxkrugger Wed, 02/13/2008 - 10:13
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What codec did you use between SIP trunk and CCM? Did u get any msg "MTPno resource available in your CCM RTMT call logs?

jeroenhermans Fri, 02/15/2008 - 10:00
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Hi,


The trunk is set to use 711Alaw.

When I check the settings of the region where my ip phone is memebr of, it says use system default. This should be 711 not sure if it is alaw or ulaw. Where can I check this?


Thanks,


Jeroen

noxkrugger Fri, 02/15/2008 - 23:16
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Hi,


Yes, correct.. the trunk should be configured to use 711ulaw...and setting at the region also for the relationship between your phone and SIP trunk also must be set as g711 not system default. If not, the phone keep sending g729 to the SIP trunk, and MTP will not be sent over it..

jeroenhermans Fri, 02/15/2008 - 23:34
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Hi,


OK, I got it to work now by manually defining the codec on the region and resetting the mtp.

Now I notice that also moh is having anissue. Whenever I place a call on hold, I just get 2 beeps. Any ideas?


Thanks,


Jeroen


Adam Frankel Sun, 02/17/2008 - 10:13
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You are hearing Tone-on-hold likely because you do not have an MOH server in the MRGL of the party being put on hold (The MRGL of the SIP trunk if the outside caller being put on hold) that contains the audio source of the party pressing hold.

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