[Devel] CANCEL to INVITE after183, Call flow question

[Klaus Darilion]

Flow 2 is correct. The Cancel is not needed as the INVITE transaction is
already finished.

klaus

On Thu, July 27, 2006 1:00, Sumeet Gupta said:
> Hello,
>
> I am having an issue regarding a particular call flow through OpenSER. I
> was
> hoping someone could clarify. Basically this vendor claims that it is
> incorrect to send a CANCEL in response to a negative INVITE even after it
> has recieved a provisional response like a 183.
>
> Call from Party A to Party B
>
> Call flow 1:
> (A) INVITE
> (B) 100
> (B) 183
> (B) 503
> (A) ACK
> (A) CANCEL
>
>
> Vendor claims it should be like this with no CANCEL.
> Call Flow 2:
> (A) INVITE
> (B) 100
> (B) 183
> (B) 503
> (A) ACK
>
> Which flow is correct?
>
> Thanks,
> Sumeet
>
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