Hi,
sipping-bounces@xxxxxxxx 写于 2010-04-21 19:55:15:
>
> Hi,
>
> >I understand that this is a very rare case,
> >
> > A B
> > | |
> > |INVITE (offer) |
> > |================================>|
> > | 1xx-rel(answer)|
> > |<===========\ /=================|
> > | \/ |
> > | /\ 18x-norel(answer)|
> > |<===========/ \=================|
> > |PRACK |
> > |-------------------------------->|
> > | |
> >
> >IIUC, if 18x-norel has a SDP(answer), UAC(A) can not insert
> >new offer into PRACK.
>
> You now seem to be suggesting that an SDP answer can be transported
> unreliably. I strongly disagree to such statement.
>
> A copy of the SDP answer can be sent unreliably, and the UAC can use
> it, but the "real" SDP answer must still be sent reliably.
I agree with Christer. And this is the same point we reached, even I think in some point, we need more proof.
>
> Maybe "ignore" is the wrong wording. The UAC cannot ignore the fact
> that the reliable response contains the SDP answer, because THAT SDP
> finishes the offer/answer transaction, but it does not need to parse it.
This is the point I talked in mail to Paul. I prefer the ini-O/A transaction finished until UAC get the answer in reliable response.
But, whether it(the SDP treated as answer in unreliable response) is the mark of "finishing of the ini-O/A transaction" is still not clear. But from engineering level, Paul has found proof that UAC and UAS can not send subsequent O/A using current defined request.
Thanks,
Gao
>
> Regards,
>
> Christer
>
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