MTP on my Inter Cluster Trunk = Dead Calls.

[Juan Gerardo Hernandez]

Hi all,

I have a Question,

Our Call Manager have a Conection with Another Call Manager (both 8.6) using a ICT Trunk (not gatekeeper controlled), On each side we have almos the identical configuration (discarting the IP's of subscribers and publishers), but on my side I have cheked the MTP option, and with that configuration we were having troubles with incoming calls.

The incomming calls, were getting ring tone and ringback tone, but when a the user pick up the phone, he gest a fast busy tone!

We were doing some test, what did the job was deactivate the MTP in the Trunk configuration of our clustes (they have it deactivated too).

I did that, because it was the only diference on both configurations, and It worked but I do not know why. Could you please explain it to me?

Regards !

[Anas Abueideh]

Hi,

the MTP is used to enable transcoding.
intercluster didn't require mtp, since you can codec negotiations by using regions

HTH
Anas


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[islam.kamal · Accepted solution]

Dear

kindly find the below

Media Termination Point (MTP) bridges the media streams between two connections allowing Cisco Unified Communications Manager to relay calls that are routed through SIP or H.323 endpoints.

The following MTP resources are supported for Cisco Unified Communications Manager

Software MTP—Software-only implementation that does not use a DSP resource for endpoints using the same codec and the same packetization time.

Hardware MTP—Hardware-only implementation that uses a DSP resource for endpoints using the same G.711 codec but a different packetization time. The repacketization requires a DSP resource so it cannot be done by software only. Cisco Unified Communications Manager also uses the term software MTP when referring to a hardware MTP.

Transcoder as MTP—Implementation that uses a DSP resource for endpoints using the same G.711 codec (on both legs) or a mixture of different supported codecs. This functionality is used by Cisco Unified Communications Manager to view the transcoders as usable MTP resources (if they are available in the pool) and enables Cisco Unified Communications Manager to use MTP resources more effectively when a call is deemed to use a transcoder and an MTP resource at the same time.

SO when intercluster you do not use MTP , when you check the call manager asked the router for DSP resouces and there is no configuration for DSP resources on router and no MTP configuration on Call manager , o the call is fail.The best is uncheck as you do

thank you

please rate if this will help

[Juan Gerardo Hernandez]

Hi, aabueideh and islam.kamal, thank you for your answers, So that is the reason!

I will review the CUCM's topic talking about media resources!.

very helpful.

regards