No Ring Back Tone after receiving 180/183(SDP) wo RTP

[m.antosik]

Hi,

I would like to ask how CUCM decides about which Ring Back Tone (Remote/Local/nothing) should be played?

There is a problem wisth 180/183 Message with SDP but without RTP. When CUCM receives that message, no Ring Back Tone is played. (CUCM 8.6 was used)

What's more:

1. When Ipphone receives 183(SDP) - remote device is sending RTP stream and later ipphone receives 180 (no SDP) -> Ipphone does not switch to play local RBT.

2. But when Ipphone receives 180(no SDP) and later Ipphone receives 183 (SDP) with RTP -> IPphone switches to play remote RBT.

Thanks for any help.

Marta

[veniciusgp]

Dear Friend,

This issue has been resolved? I have this same problem.

Best Regards

[h.hajamor]

Hi,
If there is a problem in SDP, try to check the Media Termination Point (MTP) in the device 
and if there is a trunk between phones try to check it in the Trunk.
Mabye it is a problem concerning Early Offer

[veniciusgp]

Dear Friend,

I am using cp 7821 devices with CUCM firmware but on a third party PBX using SEP XML file.

I have the following scenario:

CP 7821                                           PABX                                  CP7821

INVITE (SDP) no suported 100rel

----------------------------->

183(SDP) NO PRACK (message that the call is being transferred)

<----------------------------- 

                                                       ---------------------------> INVITE (SDP)

<--------------------------------------------------------- 180 Ringing (No SDP)

No Ring Back

Is there a solution to this problem? For example, I can enable prack support using SEP XML (auto provision)

Best Regards