Re: I-D Action: draft-ietf-httpbis-incremental-02.txt

Hello Incremental Authors and Enthusiasts,

I was in favour of this draft, but the latest additions feel over-engineered.

I think the `?0` is superfluous and unnecessarily creates a tri-state design with two identical states out of three. Especially so, if I am correct in presuming that parameters, which you have now explicitly allowed, would only apply to `?1`. My suggestion, in that case, would be to define Incremental as a Dictionary structured header instead. We could even define a key called value which is true by default. Saying "Incremental: value=?1" will be more verbose than "Incremental: ?1", but then "Incremental: prop=val" will be less verbose than "Incremental: ?1;prop=val". My intuition is that keys/parameters will become common (see next para).    


Coming to parameters, I might already have need for one. In implementing Events-Query, I have the need for servers to let clients know for how long they intend to send notifications, i.e. for how long do they intend to keep the response stream open. I am defining a custom header (actually a key called "duration" in a dictionary header) for this, but it could easily be a parameter of Incremental. More generally, I see incremental as somewhat analogous to caching with Incremental header conveying properties of about the “immediateness” of responses (things like duration, rate, and message transformation). Perhaps even an "Incremental-Control" header or "prefer: incremental-*=val" might be needed eventually?

I am in favour of the proposal for an Incremental header, but at the same time I would request more discussion on the changes proposed in the -02 draft. I think there is room for a more elegant design.

Best Regards,
Rahul


On Monday, October 20th, 2025 at 11:32 AM, internet-drafts@ietf.org <internet-drafts@ietf.org> wrote:

> Internet-Draft draft-ietf-httpbis-incremental-02.txt is now available. It is a
> work item of the HTTP (HTTPBIS) WG of the IETF.
>
> Title: Incremental HTTP Messages
> Authors: 奥 一穂 (Kazuho Oku)
> Tommy Pauly
> Martin Thomson
> Name: draft-ietf-httpbis-incremental-02.txt
> Pages: 8
> Dates: 2025-10-19
>
> Abstract:
>
> This document specifies the "Incremental" HTTP header field, which
> instructs HTTP intermediaries to forward the HTTP message
> incrementally.
>
> The IETF datatracker status page for this Internet-Draft is:
> https://datatracker.ietf.org/doc/draft-ietf-httpbis-incremental/
>
> There is also an HTML version available at:
> https://www.ietf.org/archive/id/draft-ietf-httpbis-incremental-02.html
>
> A diff from the previous version is available at:
> https://author-tools.ietf.org/iddiff?url2=draft-ietf-httpbis-incremental-02
>
> Internet-Drafts are also available by rsync at:
> rsync.ietf.org::internet-drafts
>