Fastbusy during transfer one IP phone to another

[Nikolay Kozyrev]

Hi, gent's.

Scheme:

I have local CUCM 7.1.5 at location A + far site CUCM 7.1.5 at location B. They are connected via Non-GK-Controled Intercluster Trunk.

Media Termination Point Required option are ckeck out at both site.

Phone 2222 is  registered at location A. Phone 2444 is registered at location B.

Problem:

Time to mime I've got a fast busy tone then i tryed TRANSFER call from  ext 2222 to ext 2444. Sometimes call is established and sometimes only fastbusy.

Any ideas ?

[Chris Deren · Accepted solution]

Why do you have MTP checked?  Any spcific reason for it?

Are all CUCM servers included in the ICTs?

Chris

[Nikolay Kozyrev]

Hello, Chris.

Sorry for confusion ) and bad explanation.

I mean that The Media Termination Point DOES NOT SELECTED (not checked)

[Chris Deren]

How many servers are in each cluster?

Chris

[Nikolay Kozyrev]

Hi, Chris.

Sorry for delay.

2 nodes at leach site. I suppose the problem at tanscoder. now checking that issus. I have no more ideas )

[Chris Deren]

You should not need transcoders between cisco phones even if they are on seperate clusters as the phones can negotiate the codec to agree on.  The only plan of action I see is to review the CM SDI traces to see what causes the drop.

HTH,

Chris

[Nikolay Kozyrev]

Chris.

Actually I do not understand how phones can negotiate the codec by themself. Do they have buil-in transcoder ?

According trace: What options do I need to check in ? I supose something like that

May be you will advice a programfor  trace overview in advance ?

[Chris Deren]

Yes, phones have built in DSPs that allow it to speak various codecs, so when a call is negotiated as part of the setup message phones agree on codec and they use it natively without the need for external xcoder.

You need Detailed tracing with H245 traces on.

Chris

[Nikolay Kozyrev]

Hello, Chris.

It seem to me that trascodrer is needed

Codec negotiation. I suppose i should disable g722 code.