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

Christer Holmberg <> Thu, 21 November 2013 13:05 UTC

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From: Christer Holmberg <>
To: Harald Alvestrand <>, "" <>
Thread-Topic: [rtcweb] "pranswer" be applied as an update to a previously sent "answer"?
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Date: Thu, 21 Nov 2013 13:05:41 +0000
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Subject: Re: [rtcweb] "pranswer" be applied as an update to a previously sent "answer"?
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I would assume that the text should say "update to a previously applied "pranswer".



From: rtcweb [] On Behalf Of Harald Alvestrand
Sent: 21. marraskuuta 2013 14:20
Subject: Re: [rtcweb] "pranswer" be applied as an update to a previously sent "answer"?

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?