Yes. I think it is can, not MUST.
And with precondition, the user can be hinted the new modification just after Offer/Answer pairs.
| Gonzalo Camarillo <Gonzalo.Camarillo@xxxxxxxxxxxx>
2009-02-27 18:22 |
|
Hi,
UEB would have rejected the video stream in the 183 response.
Gonzalo
wang.libo@xxxxxxxxxx wrote:
>
> HI,
>
> I think the video will be established.The figure below shows the case.
>
>
> 1. REINVITE(audio，vedio)
> ----------------------------->
> 2. 183
> <-----------------------------
> 3. PRACK/200
> <------------------------------>
> 4. UPDATE(audio，vedio)
> ----------------------------->
> 5. 200(audio，vedio)
> <-----------------------------
>
> 6. 4XX
> <-----------------------------
>
> After step 5, UEs' precondition are met ,and the video stream is
> established too.
> But UE-B send 4xx to reject 4XX (step 6).
>
> Regards.
>
>
>
>
> *Gonzalo Camarillo <Gonzalo.Camarillo@xxxxxxxxxxxx>*
>
> 2009-02-27 17:30
>
>
> 收件人
> wang.libo@xxxxxxxxxx
> 抄送
> christer.holmberg@xxxxxxxxxxxx, gao.yang2@xxxxxxxxxx, sipping@xxxxxxxx,
> sipping-bounces@xxxxxxxx
> 主题
> Re: 答复: Re: ??: Re: [Sipping] ??: Re: ??: Re: ??: Re: ??: Re: ??:
> Re: ??: Re: Closing the offer/answer rollback issue
>
>
>
>
>
>
>
>
> Hi,
>
> > If UE-A wants to communicate with UE-B by video, but UE-B only want to
> > communicate by audio.
>
> then UE-B rejects the video stream and the video stream is never
> established.
>
> Cheers,
>
> Gonzalo
>
>
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