Re: Prioritizing HTTP DATAGRAMs

Hi Lucas,

I agree with this approach. Getting more deployment experience with
datagrams, and with priorities (separately) is bound to teach us some
lessons about both. Armed with those lessons, we'll be able to write a
separate draft for how the two interact best.

David

On Tue, Jun 22, 2021 at 6:40 AM Lucas Pardue <lucaspardue.24.7@gmail.com>
wrote:

> Hello HTTP and MASQUE,
>
> Over the last couple of months, the question about prioritization with
> respect to HTTP DATAGRAMs has come up first in MASQUE issue # 46 [1] and
> then HTTP issue #1550 [2], which was also discussed during the recent HTTP
> interim.
>
> Extensible priorities is pretty far along it's journey, which has so far
> been focused on HTTP message content (and CONNECT tunnel data, see PR #1544
> [3]). The scheme fulfills the needs of the base HTTP/2 and HTTP/3
> specifications, and so far hasn't considered extensions. Extensible
> priorities acts as a replacement for HTTP/2's prioritization scheme, while
> being the only known scheme defined for HTTP/3. However, there is nothing
> to prevent alternate schemes being defined or used in the future (although
> we hope the need for that can be avoided by the extensibility here).
>
> Endpoints that send DATAGRAM flows concurrently with other flows or
> streams have to make scheduling decisions. Therefore, the question about
> how to prioritize them, and to communicate that via signals, is a good one.
> However, currently the editors of draft-ietf-masque-h3-datagram and
> draft-ietf-httpbis-priority (disclosure: I am co-editor on both) feel that
> linking these two drafts directly is not the best approach for either.
>
> On draft-ietf-masque-h3-datagram issue #46 [1], we resolved the discussion
> by adding text to say that prioritization of HTTP/3 datagrams is not
> defined by the document.
>
> For draft-ietf-masque-h3-datagram issue #1550 [2], the proposed resolution
> is PR #1559 [4]. The PR adds a clear statement that the document is focused
> on HTTP content and CONNECT tunnel data. It also makes clear that
> extensions like DATAGRAM can also use the scheme but punts that to their
> court.
>
> Kazuho and I are seeking some feedback for PR #1559 [4] before landing it.
> We appreciate that this leaves a gap for DATAGRAM priorities, especially
> since DATAGRAM says nothing. But the thought process is that another
> Internet-Draft could fill this gap. This would create an indirect
> relationship that would allow documents to progress independently. I'm
> planning to start a draft soon and have it ready by IETF 111. Which WG it
> should belong to is probably another matter for debate.
>
> Cheers
> Lucas
> Wearing co-editor hat for HTTP/3 DATAGRAM and Extensible priorities
>
>
> [1]
> https://github.com/ietf-wg-masque/draft-ietf-masque-h3-datagram/issues/46
> [2] https://github.com/httpwg/http-extensions/issues/1550
> [3] https://github.com/httpwg/http-extensions/pull/1544
> [4] https://github.com/httpwg/http-extensions/pull/1559
>