H323 - H323 voice gateway,Incoming disconnects in 10 second, no audio

[fazlayrabby]

Dear All,

I am trying to connect CUCM v7.1 to a provider who is using H323.

Outgoing from CUCM is working ok

Incoming not working (DID extension rings, connects, but no audio and get disconnects after 10 seconds, main number connects but no voice greetings and also disconnects after 14-15 seconds).

Configuration of the 2811 gateway and trace of cch323 session is attached.

Appreciate if you can see whats I am doing wrong here.

My IOS: C2800NM-SPSERVICESK9-M), Version 12.4(3i), RELEASE SOFTWARE (fc2)

CUCM has region G729 for the gateway DP. (service provider is using 729)

Many thanks in advance.

Fazlay

UNICEF Bangladesh

[fazlayrabby]

Hi Carlo,

Call start internet is not a valid command for this IOS. Valid commands are Fast, Interwork, Slow.

I have tried Call Start Interwork but without any luck. Still call drops at 11 seconds. Thanks in advance.

Fazlay

[Udit Mehrotra]

Even though the H245 Address and port is recieved H245 is never initiated.

CUCM has an option for "Wait for far end H245 TCS" on CUCM which is checked by default. So CUCM will never initiate TCS until it recieves TCS from gateway. Gateway will not initiate TCS as the provider has not sent TCS.

This is kind of a race condition where in every device is waiting for the other device to initiate TCS.

Please uncheck "Wait for far end H245 TCS" on CUCM H323 gateway page and it should solve the problem.

If you still face the issue, please collect the same set of debugs and attach to post.

HTH

-=-

Udit

[fazlayrabby]

Dear Udit,

Thanks for reply.

The wait for far end h245 TCS is unchecked from the begining as enabling it was giving outgoing problem.

I was doing some experiment, If I enable Media Termination Point required, then the call doesnt disconnects in 10 seconds, but there is no audio for incoming call. and also for outgoing (which works w/o MTP before) the call disconnects imidiately after answering. I was using IOS MTP in same box having G729r8 codec mentioned. I have PVDM 2-16 so using the Software MTP insted.

I hope this will help you understand the problem.

Thanks.

Fazlay

[fazlayrabby]

Hello Udit and Carlo,

There is some improvement. The service provider manage to enable G711 for us. I have donw the following:

Change the codec preference to:

1. G711ulaw

2. G711alaw

Change the region settings to G711 in CUCM for this GW

Now: Outgoing works like before. Incoming connects but no audio (dowsnt disconet at 11 second like before)

I have done some test: If I dont give "call start interwork"  under voice service voup>>h323 then the incoming call drops in 11 second like before. Any other setting like call start fast/slow also disconnect in 11 second.

Having MTP enable has no effect, it is disable now like before. Please have a look of the ccapi/h225asn1/h245asn1 debug.

Thanks in advance.

Fazlay

[Udit Mehrotra]

This is an interesting problem. CUBE is not sending Connect to provider instead it is sending Progress to negotiate H245 before call connect.

Please try the following command and let me know if it helps.

!

voice service voip

h323

  h225 connect-passthru

!

I do not know right now if above would solve the problem but its worth a try. Please update the thread and let us know the outcome.

-=-

Udit

[fazlayrabby]

Dear Udit,

That command is already in the configuration. No luck

Some more improvement. I asked the Service Provider to send calls to me using SIP. Following is the result:

1. Outgoing: CUCM--------IPIPGW---------SP : Works OK

2. Incoming: SP------IPIPGW--------CUCM

A. When incoming calls come to Direct extension 7281(DID 09604107281) it works ok,

Problem: If the calls is transfered before other extension answers: it connects but no audio. If the other party answers before transfer then everything works OK. Caller can here MOH while transfering (caller can hear ringback after transfering if its a blind transfer)

B. When called to the pilot number 09604107000  ( in cucm 0000 is forwarded to 19026/unity greetings ) caller hear greetings, after pressing extension number call get transfered but no audio. [[similar to a blind transfer i guess as above]]

I am attaching the config and trace for Debug ccapi inout + ccsip message.

I am desparate to make this trunk operational for the users here. It seems we are almost there to make it happen. Please advise.

Thanks in advance.

Fazlay

[Udit Mehrotra · Accepted solution]

Try the following -

!

voice service voip

sip

  no update caller-id

!

Let us know the outcome.

-=-

Udit

[fazlayrabby]

Dear Udit,

I have added The command no update caller-id, still same issue.

I am not sure if Call transfer require Conference bridge and MTP, should I check those?

Thanks for your help.

Fazlay

[david-lima]

Hi, for SIP call transfer, try adding the "no supplementary-service sip refer" under voice service voip mode.

hth

David

[fazlayrabby]

Dear All,

The transfer problem has been solved after checking MTP on. In the begining making MTP on creates lot of problem, but now at the end it solved the problem. Thanks all for your support.

Fazlay

[Mauro Tartara]

Hi Fazlay,

Can you tell me how you check MTP on?

Thanks

[fazlayrabby]

Hi Mauro

In CUCM administration, under TRUNK configuration if "Media Termination Point Required" is checked that means MTP is on. Hope it would help you. Thanks.