SIP Third Party

[Giovanni Sciotti]

Hello,

we are facing a behavior with SIP third Party devices on cucm 8.6.2aSU3

The behavior is that in every call the device use the callmanager as MTP to place the call and the RTP stream is always through the callmanager.

We would like that the RTP goes directly between the devices as happens with Cisco IP Phones.

Bye

Giovanni

[Frankaviglia]

Maybe the two SIP devices do not have compatible codecs so they are going through an MTP to comply with the audio capabilities? You should try and check SDP message exchange between the two using RTMT Traces.

Also make sure that within the SIP Profile the flag "Media Termination Point Required" is not checked.

Ciao,

Francesco

[Giovanni Sciotti]

Hello,

we made some test and the problem is only in calls to PSTN.

internal calls works fine with RTP between endpoints.

The Voice Gateway is connected in H.323 with Callmanager.

Giovanni

[Frankaviglia]

Is the GW a Cisco Device? What codecs are allowed within the dial-peer?

[Giovanni Sciotti]

Yes, a cisco 2921 with IOS: c2900-universalk9-mz.SPA.152-4.M2.bin

voice class codec 1

codec preference 1 g711ulaw

codec preference 2 g711alaw

codec preference 3 g729r8

These codecs are applied in the dial peers.

Giovanni

[Manish Prasad]

Is -Media Termination Point Required -option checked in h323 gw in cucm?

[Giovanni Sciotti]

Hello,

no it is not checked.

I tried configuring a SIP trunk to the Voice Gateway and a Dedicated Route Pattern to my mobile number to make a test.

And the RTP streaming goes directly between the SIP third party device and the Voice Gateway.

The problem is if you have a customer with hundreds of H323 Voice Gateway is not so good to change all the architecture setting up SIP trunks in all sites.

Anyone is able to get direct RTP between the SIP third party device and the Voice Gateway using H323 protocol?

Thank you

Giovanni

[Jagpreet Singh]

Hello,

     The MTP is most probably being alocated due to a DTMF mismatch. The third party SIP phone is using Inband DTMF but an H.323 gateway can only to Out of band DTMF with the CUCM. Thus we need an MTP to achieve this.

Regards,

Jagpreet

[Giovanni Sciotti]

Hello Jagpreet,

thank you for the information.

So is it impossible to use third party with H323 gateway correctly?

Isn't there any workaround in your opinion?

Thank you.

Giovanni