Re: [Sip] Question on Unify draft

Gonzalo Camarillo wrote:
> 
> Hello,
> 
> "Chen, Xin (Xin)" wrote:
> >
> > In this draft, in figure 4 (solution for One-of-N Codecs problem), it uses
> > the a=inactive in the first offer to stop the callee to send media. But is
> > it possible that the callee answers the offer by changing the a=inactive to
> > a=active and starts to send media immediately?
> >
> > If this is possible, then this solution won't work, am I right?
> >
> 
> The direction attribute cannot be change in the answer. It has to be the
> same as in the offer. See:
> http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sdp-offer-answer-01.txt

Well, it can change it, but in this specific case, it cannot. If can
basically be "downgraded", but not "upgraded" in the answer. Since
inactive is the lowest "grade", it cannot be downgraded further and thus
cannot change.

-Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.            72 Eagle Rock Avenue
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