Re: [Webtransport] WG Review: WebTransport (webtrans)

Hi Spencer,

The main goal is for WebTransport to use QUIC and benefit
from QUIC features such as reduced head-of-line blocking.
However, on networks where QUIC is blocked, the WG will
most likely define a fallback version over TLS/TCP. That
version will obviously not see QUIC features. I think this fits
into the proposed charter, as it requires paying attention to
these concerns.

We explicitly chose not to specify which exact protocols
WebTransport will be built on in the charter, because we
have not reached consensus on that yet, and this will be
discussed in the newly formed WG.

Thanks,
David

On Fri, Feb 14, 2020 at 12:15 PM Spencer Dawkins at IETF <
spencerdawkins.ietf@gmail.com> wrote:

> As usual, I'm reading this, and not just looking at the words (as
> previously).
>
> Most of it looks fine, except for the part where I fell off the edge of
> the cliff.
>
> On Fri, Feb 14, 2020 at 9:20 AM The IESG <iesg-secretary@ietf.org> wrote:
>
>> A new IETF WG has been proposed in the Applications and Real-Time Area.
>> The
>> IESG has not made any determination yet. The following draft charter was
>> submitted, and is provided for informational purposes only. Please send
>> your
>> comments to the IESG mailing list (iesg@ietf.org) by 2020-02-24.
>>
>> WebTransport (webtrans)
>> -----------------------------------------------------------------------
>> Current status: Proposed WG
>>
>> Chairs:
>>   Bernard Aboba <bernard.aboba@gmail.com>
>>   David Schinazi <dschinazi.ietf@gmail.com>
>>
>> Assigned Area Director:
>>   Barry Leiba <barryleiba@computer.org>
>>
>> Applications and Real-Time Area Directors:
>>   Adam Roach <adam@nostrum.com>
>>   Alexey Melnikov <aamelnikov@fastmail.fm>
>>   Barry Leiba <barryleiba@computer.org>
>>
>> Mailing list:
>>   Address: webtransport@ietf.org
>>   To subscribe: https://www.ietf.org/mailman/listinfo/webtransport
>>   Archive: https://mailarchive.ietf.org/arch/browse/webtransport/
>>
>> Group page: https://datatracker.ietf.org/group/webtrans/
>>
>> Charter: https://datatracker.ietf.org/doc/charter-ietf-webtrans/
>>
>> Description of Working Group
>>
>> The WebTransport working group will define new client-server protocols or
>> protocol extensions in order to support the development of the
>> WebTransport
>> API https://wicg.github.io/web-transport.
>>
>> The WebTransport working group will define an application-layer protocol
>> or suite of application-layer protocols that support a range of simple
>> communication methods. These must include unreliable messages (that might
>> be limited by the path MTU), reliable messages, and ordered streams of
>> reliable messages. Attention will be paid to the performance of the
>> protocol, with particular attention to the protocol’s overhead and the
>> potential for head-of-line blocking; its ability to be deployed and used
>>
>
> Speaking of "head of line blocking" ...
>
>
>> reliably under different network conditions; and its ability to integrate
>> into the Web security model. The working group will not define new
>> transport protocols but will instead use existing protocols such as QUIC
>> and TLS/TCP.
>>
>
>  Is the intention here to allow applications using WebTransport to do
> something like what applications using HTTP/3-QUIC do today, and failover
> to HTTP/2-TLS-TCP if QUIC is blocked or significantly rate-limited?
>
> If "Yes", that might be said more clearly.
>
> If "No" - how badly does the world need WebTransport for TLS/TCP?
>
> I ask this especially because the charter raises head of line blocking as
> a consideration - as it should, in 2020 - but TLS/TCP hasn't changed about
> that since QUIC was chartered in 2016, with avoiding TCP head of line
> blocking as a key goal. So listing QUIC and TLS/TCP as apparently equally
> legit existing protocols seems odd.
>
> Could someone clue me in about this?
>
> Best,
>
> Spencer, who is also curious about possible coordination between
> WebTransport and TAPS, but let's ignore that for now.
>
> The group will pay attention to security issues arising from the above
>> scenarios so as to protect against creation of new modes of attack.
>>
>> To assist in the coordination with owners of the WebTransport API, the
>> group will initially develop an overview document containing use cases
>> and requirements in order to clarify the goals of the effort. The
>> requirements will include those arising from the WebTransport API.
>> Feedback will also be solicited at various points along the way in order
>> to ensure the best possible match between the protocol extensions and the
>> needs of the WebTransport API.
>>
>> The group will also coordinate with related working groups within the
>> IETF,
>> such as QUIC and HTTPBIS, as appropriate.  In particular, if the working
>> group needs any changes to or extensions of the core protocols, those
>> issues will be raised with the relevant working groups for decisions on
>> how
>> best to handle them.  If those decisions result in work in WebTrans, the
>> working group last calls for that work will again be sent to the relevant
>> working groups.
>>
>> Milestones:
>>
>>   Mar 2020 - Adopt a WebTransport Overview draft as a WG work item
>>
>>   Mar 2020 - Adopt a draft defining a WebTransport protocol as a WG work
>> item
>>
>>   Oct 2020 - Issue WG last call of the WebTransport Overview document.
>>
>>   Jan 2021 - Issue WG last call on the first WebTransport protocol
>> document
>>
>>
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>>
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