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[Sip] Re: Offer by the callee
Hi,
Setting the port number to zero means refusal of the stream, so you are
risking that the caller sends a CANCEL, since you have refused all the
media streams. A better solution would be to send a held SDP
(a=inactive).
Regards,
Gonzalo
Juan-Carlos.Rojas@alcatel.fr wrote:
>
> Hello,
>
> I'm trying to connect the offer/answer, update and manyfolks drafts for the
> following scenario:
> - Alice sends an INVITE to Bob with "offer-1"
> - Bob wants to make an "offer-2" to Alice, before the completion of the
> session establishment
> - Bob would like to ask Alice to start resource reservation only based on
> the acceptation of "offer-2", and not before (in fact Bob knows that it is
> useless to start resource reservation based on offer-1, because he knows he
> will send immediatly a new offer-2, but he is obliged to wait for Prack
> before)
>
> The Update draft defines the response 155 to allow the answerer (the callee
> in our case) to request "Mr. the calling, please *send me* a new offer",
> but there is no way for the same callee to announce "Mr. the calling, *I
> want to send you* a new offer right now".
> So, one possible way to achieve that is that the callee sends an answer to
> the original offer but disabling all the media (in order to avoid to start
> resource reservation), and next proposing a new offer, as described in the
> call flow below (assume for the example that they are using end-to-end
> resource reservation, but please don't generate a new debate on this
> topic):
>
> Alice
> Bob
> INVITE (offer-1)
> ----------------------------------------------------------------->
> 183 (answer-to-offer-1, all port numbers to zero)
> <-----------------------------------------------------------------
> PRACK
> ----------------------------------------------------------------->
> 200 PRACK
> <-----------------------------------------------------------------
> UPDATE (offer-2, status-type=e2e)
> <-----------------------------------------------------------------
> 200 UPDATE (answer-to-offer-2)
> ----------------------------------------------------------------->
>
> <========== Resource Reservation ==========>
>
> UPDATE (current-status = desired-status)
> ----------------------------------------------------------------->
> 200 UPDATE
> <-----------------------------------------------------------------
> 200 INVITE
> <-----------------------------------------------------------------
> ACK
> ----------------------------------------------------------------->
>
> Is this scenario compliant with the drafts Offer/Answer, Update and
> Manyfolks ?
>
> Thank you for your answer
> Best regards
> Juan Carlos
--
Gonzalo Camarillo Phone : +1 212 939 71 71
Columbia University Mobile: +358 40 702 35 35
472 Computer Science Building Fax : +358 9 299 30 52
1214 Amsterdam Ave., Mail Code 0401 http://www.hut.fi/~gonzalo
New York, NY 10027
USA Gonzalo.Camarillo@ericsson.com
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