Subject: RE: [Sipping] BCP for Offer/Answer Use - PLEASE COMMENT

From: "Christer Holmberg (JO/LMF)" <[email-masked]>
Date: Wed, 2 Nov 2005 16:52:02 +0100

Hi, 

>>If we could reject the offer by using specific parameter 
>>values in the "answer" it would solve lots of problem, I think, but
that 
>>would need to be defined.
>
>Yes, there is currently no defined way to do that.
> 
>>I guess setting the port to zero could be used already with 
>>the existing specifications, but the problem is that the calling party
would then
>>have to send a new offer with a new stream, since the 
>>stream with the zero port can't be "re-used".
> 
>There was once a restriction like that, but no more.
>You may recycle the media lines in a subsequent offer.

Yes, when thinking about it, that is correct.

So, I guess that could be one option. Of course, the offerer won't know
why the offer was rejected (it may think the specific media type
suddenly isn't supported anymore, or that there are no resources for
that specific stream). But, if we include words saying that PRACK should
only be used for relatively "safe" offers thay may not be a problem.

Regards,

Christer

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From: Gonzalo Camarillo <[email-masked]>
Date: Wed, 02 Nov 2005 19:17:48 +0200

Hi,

 > But, if we include words saying that PRACK should

I thought we had added a warning along those lines in one of the specs 
(RFC 3261, RFC 3262, or RFC 3264), but now I cannot find it. Does 
anybody remember in which spec it is?... or maybe we simply forgot to 
add it.

Gonzalo