[OpenSIPS-Users] Problem with prefix() during call forwarding

Andrew Pogrebennyk andrew.pogrebennyk at portaone.com
Tue Nov 24 23:38:19 CET 2009

I have put b2bua between OpenSIPS and Cisco, but still no luck. The 
point here is that when fr_inv_timer hits, OpenSIPS prematurely sends 
INVITE per the next branch and only after that CANCELs the previous one. 
I don't think this is the correct behavior actually, and there was a 
similar issue mentioned in the Kamailio mailing list: 
If I can make OpenSIPS to wait for the fist branch to be canceled, I 
will invent something in the b2bua to make it finally work. However I 
understand that in general serial forking to one destination won't work.

Andrew Pogrebennyk wrote:
> Bogdan,
> Thanks. I'm using 1.5.3. I sort of got stuck with this serial forking 
> scenario. I mean, OpenSIPS does what is supposed to do. The problems is 
> the call needs to be sent to (and is originated by) the Cisco AS5300. 
> When one destination fails OpenSIPS sends the call to the next 
> destination, but since new INVITE is part of the same dialog for 
> OpenSIPS is carries the same Call-ID and From tag the Cisco gets 
> confused and sends 482 Loop Detected or 500 Internal Server Error. 
> Perhaps delaying new INVITE by a few ms for the Cisco to invalidate the 
> call state would have helped, but I can't find my way around this.
> Regards,
> Andrew

Andrew Pogrebennyk

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