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

[Justin Uberti <[e-mail]>]

On Fri, Feb 8, 2019 at 11:15 AM Roman Shpount <[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]> 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
>>
>>
>> _______________________________________________
>> rtcweb mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/rtcweb
>>
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