Re: [rtcweb] Call for consensus on ICE transport parameter issue (February 15).

[Christer Holmberg <[e-mail]>]

Hi,

I also support this change.

I share Roman’s issue in this note #1, but since Justin seems to be fine removing the associated text it should be solved.

Regards,

Christer

From: rtcweb <[e-mail]> on behalf of Justin Uberti <juberti=[e-mail]>
Date: Friday, 8 February 2019 at 20.21
To: Roman Shpount <[e-mail]>
Cc: "[e-mail]" <[e-mail]>
Subject: Re: [rtcweb] Call for consensus on ICE transport parameter issue (February 15).



On Fri, Feb 8, 2019 at 11:15 AM Roman Shpount <[e-mail]<mailto:[e-mail]>> wrote:
I am, obviously for this change. As far as I know additional complexity is minimal if not completely non-existent. JSEP already requires m= and c= line updates based on the default candidate. I do not think there is a lot of extra effort in updating the same line based on the same input in two places vs one place.

I would also like to note that:

1.  JSEP requires browsers to update the m= line more often then mmusic-ice-sip-sdp or RFC 5245. For offers sent during ICE nomination process, JSEP asks to set m= and c= line to the last used ICE candidate pair. RFC 5245 asks in this case to set this to the default candidate pair, which changes a lot less often. It is unclear what is the benefit of additional JSEP requirement. It looks like some sort of left over logic from re-nomination. This being said, it should not create any interop issues and will simply creates additional complexity.

I agree that this should probably be removed from JSEP and codified in sip-sdp instead; as previously discussed, JSEP doesn't actually use this info.

2. JSEP can produce the answer where default candidate protocol does not match the m= line protocol. This is an old RFC 5245 issue and can be fixed in the future specification or mmusic-ice-sip-sdp.

This should probably also be fixed in sip-sdp.

Regards,
_____________
Roman Shpount


On Fri, Feb 8, 2019 at 1:43 PM Ted Hardie <[e-mail]<mailto:[e-mail]>> wrote:
Over the the past few weeks, the working group has discussed whether to adopt a change to JSEP which would adjust how the ICE proto line transport parameters are populated in certain mid-session offers where the final candidate is a TCP candidate.  Outside of the extensive working group discussion on the mailing list, participants may also wish to review the follow issue:

https://github.com/rtcweb-wg/jsep/issues/854

and the conversations related to these two pull requests:

https://github.com/rtcweb-wg/jsep/pull/862
and
https://github.com/rtcweb-wg/jsep/pull/863

The chairs believe that there is technical consensus that this proposed change would not materially affect JSEP-only exchanges, since this parameter is ignored in those.

The remaining technical issues are:

* whether making one of these changes would improve interoperability between WebRTC and non-WebRTC clients which use SIP/SDP.

* whether the additional complexity in tracking the use of UDP vs. TCP and populating the parameter accordingly is onerous or unwarranted for WebRTC implementations.

After reviewing the discussion to date, the chairs believe that there is rough consensus for the first point, though there is also broad agreement that the benefit of this change is currently theoretical, since no existing WebRTC browser implementation has relevant code.

On the second point, the chairs believe that there is no consensus yet demonstrated.  Because we believe that this is in part because the actual proposal has not been entirely clear, and the complexity is therefore somewhat hard to gauge, the chairs wish to make a specific call for consensus.

Does the working group approve the change in the following PR:

https://github.com/rtcweb-wg/jsep/pull/863 ?

Working group participants who have objections to the change are asked to specify whether they believe it has a technical fault, whether they object on the basis of its complexity, or whether they have other issues related to the change they need to raise.

The chairs are already aware of the objection of Eric Rescorla on the basis of complexity, and will factor it into the review.

Please send comments by February 15th, 2019.

regards,

Ted Hardie and Sean Turner


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