W3C home > Mailing lists > Public > ietf-http-wg@w3.org > July to September 2014

Re: Getting to Consensus: CONTINUATION-related issues

From: Michael Sweet <msweet@apple.com>
Date: Fri, 18 Jul 2014 07:36:49 -0400
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Message-id: <B4669E3C-4A55-4BC9-8B66-F8C2D0AAC625@apple.com>
To: Mark Nottingham <mnot@mnot.net>
Prefer A, can't live with B because with large frames it would mean sifting through potentially 2^24-1 per frame of extra compressed header data, assuming you even wanted to leave the connection up at that point.  We already place a tremendous burden on the endpoints to support HPACK (compared to sending headers the HTTP/1.1 way) - with a single limit upfront we can control the size of that burden for everyone.


On Jul 17, 2014, at 8:44 PM, Mark Nottingham <mnot@mnot.net> wrote:

> We've had a rollicking discussion about the design tradeoffs in CONTINUATION, especially regarding HOL blocking and DoS considerations.
> 
> I see very little new information entering that discussion, and I think everyone has come to understand the tradeoffs. For a refresher, please see the wiki:
>  https://github.com/http2/http2-spec/wiki/ContinuationProposals
> 
> I proposed two options the other day:
> 
> a) Remove CONTINUATION from the specification and add a new setting that dictates the maximum HEADERS/PUSH_PROMISE frame size (as distinct from max_frame_size) a peer is willing to receive. I.e., the setting refers to the compressed header size.
> 
> b) Keep CONTINUATION in the specification, and add a new setting that advises the maximum header set size (i.e,. uncompressed) a peer is willing to receive (but might not imply PROTOCOL_ERROR or STREAM_ERROR on receipt).
> 
> Although there have been some tentative proposals for additional options since, I haven't heard a clamour for support for them, so I think these are realistically the ways we can go.
> 
> As stated before, there will no doubt be tweaking and adjustments made to these, but I think we're in a place where we can choose a general direction.
> 
> I'd like to hear:
> 
> 1) Your preferred outcome (if any)
> 2) Whether you can live with the other option, and if not, why
> 
> "I have no preference" is useful information too.
> 
> If you indicate you can't live with one (or both) of the options, you MUST give a detailed, relevant reason as to why; omitting the reason means your "can't live with" will be ignored.
> 
> Thanks,
> 
> P.S. Please state *your* preference, not what you think the WG can live with.
> 
> P.P.S. This is not a call for more discussion; please resist replying to others' preferences.
> 
> 
> --
> Mark Nottingham   https://www.mnot.net/
> 
> 
> 
> 
> 

_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair



Received on Friday, 18 July 2014 11:37:21 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 30 March 2016 09:57:09 UTC