Re: [rtcweb] "pranswer" be applied as an update to a previously sent "answer"?

[Harald Alvestrand <[e-mail]>]

On 11/20/2013 12:22 PM, Lijing (Jessie) wrote:
>
> draft-ietf-rtcweb-jsep-05 -----Section 4.1.3 says:
>
> "pranswer" indicates that a description should be parsed as an
>
>    answer, but not a final answer, and so should not result in the
>
>    freeing of allocated resources.  It may result in the start of media
>
>    transmission, if the answer does not specify an inactive media
>
>    direction.  A description used as a "pranswer" may be applied as a
>
>    response to an "offer", or an update to a previously sent "answer".
>
> How can a pranswer be applied as an update to a previously sent 
> answer?  I am not sure what's the corresponding scenario.
>
> From the state machine perspective, when answer is received, it enters 
> the stable state. At this point, the state machine can not directly 
> jump to local pranswer or remote pranswer state.
>
> My two cents: May be it needs more description or correction here.
>

This makes sense, and is consistent with the state diagrams, if the last 
"answer" is changed to "pranswer".

Justin, is this an error in the draft?