Calls keeps on ringing to caller if disconnected by called party

[Karan Sharma]

Hi all,

We are facing issue with outbound call. If we are calling any mobile number from jabber and called party is directly disconnecting call (without answering) call keeps on ringing around 30 sec. It's not disconnecting instantly.

I can see in GW debug, 480 temporary unavailable response is delayed from service provider.

Is there any configuration needed on CUCM?

[OnkarMahajan38629]

Yes, you can try to fix it from CUCM side.

I believe, the delay of 30 seconds you are referring to is actually the announcement by service provider something like "Number you are dialing is currently busy..." or it could be even a voicemail greeting from destination number. From the capture I think it must have started at 08:05:28 when you see 183 Session Progress coming from provider. After the announcement service provider disconnected the call at 08:56:11 by sending 480 Temporarily unavailable. The problem could be caller is not able to hear the announcement hence has impression than destination is still ringing. 

From the capture screenshot I can say that the caller will not hear the announcement because CUCM is sending delayed INVITE and PRACK is disabled on hence there is no two way audio negotiated between CUCM and GW.  

Enable PRACK on CUCM by going into SIP trunk SIP profile and change 'SIP Rel1XX Options' to 'Send PRACK if 1xx Contains SDP' (or 'Send PRACK for all 1xx Messages), default is Disabled.

Regards,

Onkar Mahajan

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