Re: [Webtransport] Magnus Westerlund's Block on charter-ietf-webtrans-00-00: (with BLOCK and COMMENT)

[Ted Hardie <[e-mail]>]

Howdy Magnus,

One small point, below.

On Fri, Jan 31, 2020 at 8:39 AM Magnus Westerlund via Datatracker <
[e-mail]> wrote:

> Magnus Westerlund has entered the following ballot position for
> charter-ietf-webtrans-00-00: Block
>
> When responding, please keep the subject line intact and reply to all
> email addresses included in the To and CC lines. (Feel free to cut this
> introductory paragraph, however.)
>
>
>
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/charter-ietf-webtrans/
>
>
>
> ----------------------------------------------------------------------
> BLOCK:
> ----------------------------------------------------------------------
>
> This charter is so open ended on what protocol that is to be developed
> that it
> could define a new IP version as well as transport protocols. I don't think
> that is the intention. To my understanding this effort could more clearly
> be
> defined as defining one or two application protocol that fulfills the
> WebTransport API and is using QUIC or HTTP/3. If the charter can be
> clarified
> to not include transport protocol work and which existing transport
> protocols
> or other protocols the solution will build on it would be much better and
> well
> defined work. I also think creating mappings to other transport protocols
> should require rechartering to enable a wider discussion of such choices.
>
> Secondly:
>
> The group will also coordinate with related working groups within the IETF,
> such as QUIC and HTTPBIS, as appropriate.
>
> With the current state of QUIC developement and HTTP/3 mapping definition,
> i.e.
> still working on the initial version, I would like to have a more firm
> wording
> that the WebTrans WG will actually have to take any requests for
> extensions of
> HTTP/3 and QUIC to the relevant WG.
>
>
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
>
> I also would appreciate if someone can clarify what stage of formality the
> Web-Transport API has been adopted in W3C and is being worked on. Trying to
> find anything about which group it belongs to on the W3C page didn't give
> me
> any information. All I found is that there have been a workshop on game
> communication where this was discussed and raised in some discussions.
>
> Having lived through the WebRTC / RTCWeb interactions it would good to know
> more how the interaction between the bodies are intended to work.
> Especially as
> changes to the API can have significant impact on what work needs to
> happen in
> the IETF.
>
> The current API draft does not include any discussion of priority. However
> draft-vvv-webtrans-overview does mention priorities. As this API appears to
> support multiple parallel transmissions and transfers I think at a minimal
> a
> sender transport protocol scheduling or HTTP/3 priority  would be likely
> to be
> part of the work.


HTTP/3 priority is, uh, well, um, here's the draft:
A.2.1.
<https://quicwg.org/base-drafts/draft-ietf-quic-http.html#section-a.2.1>Prioritization
Differences
<https://quicwg.org/base-drafts/draft-ietf-quic-http.html#name-prioritization-differences>

HTTP/2 specifies priority assignments in PRIORITY frames and (optionally)
in HEADERS frames. HTTP/3 does not provide a means of signaling priority.
Note that while there is no explicit signaling for priority, this does not
mean that prioritization is not important for achieving good performance.

The working group has been up and down that hill and eventually decided not
to die on it, so that the work could go forward more rapidly.  If you'd
like to grab someone for the backstory, Jana or Roberto Peon would be
possible choices.


> I also have to ask if this is likely to attempted to be
> mapped also towards the network level, for example DSCPs? If any such work
> is
> expected and intended I think that needs to be raised. Otherwise I would
> assume
> that at most what this work will be to use the undefined APIs to HTTP/3 and
> QUIC to influence those protocol to perform stream priorities.
>

regards,

Ted