[OpenSIPS-Users] parallel forking and CANCEL/BYE

[Bogdan-Andrei Iancu]

Hi Uwe,

Uwe Kastens wrote:
> Hi Bogdan,
>
>   
>> So actually both legs do send 200 OK (but one faster than the 
>> other)......so there is kind on race between the 200 OK from the slow 
>> branch and the CANCEL from OpenSIPS...is this the case?
>>     
>
> Exactly
>
>   
>> If so, the UAS will simply reply with negative reply to CANCEL (decline 
>> it) and opensips (for INVITE transaction) will not close the second 
>> branch as there is a 200 OK (and not a 487) received ....RFC3261 says 
>> that a proxy must send all 200 OK (for a call), even if more than one, 
>> to the UAC - the UAC is the one who will decide what branch to keep and 
>> it will fire a BYE for the other branch.
>>
>>     
>
> Could this explan, why only the 2nd Node will get the BYE, if the call
> is released "behind" the opensips?
>   
yes, because the caller will hung up only one of the callee branch, so 
the BYE will go to only one of them. The other branch will remain up and 
will be the ongoing call.

Regards,
Bogdan