Re: draft-ietf-quic-http-29, "1.1. Prior versions of HTTP"

"Roy T. Fielding" <fielding@gbiv.com> Fri, 19 June 2020 17:33 UTC

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Subject: Re: draft-ietf-quic-http-29, "1.1. Prior versions of HTTP"
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From: "Roy T. Fielding" <fielding@gbiv.com>
In-Reply-To: <9B975808-6BF3-491C-8E32-C475824B0E9A@mnot.net>
Date: Fri, 19 Jun 2020 10:33:19 -0700
Cc: Julian Reschke <julian.reschke@gmx.de>, quic@ietf.org
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References: <8c747b59-1672-4ccb-dfce-0914e74c504f@gmx.de> <9B975808-6BF3-491C-8E32-C475824B0E9A@mnot.net>
To: Mark Nottingham <mnot@mnot.net>
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> On Jun 18, 2020, at 4:19 PM, Mark Nottingham <mnot@mnot.net> wrote:
> 
> My .02 -
> 
> I think we need to balance between being correct and over-complicating the text here. In *theory*, Julian is correct; in wide practice, pipelining isn't used because of the limitations it has, as well as implementation / interop issues.

No, it isn't used by browsers because they aren't aware of the purpose
for each connection and request. API clients almost always use pipelines.

> How about something like:
> 
> "Because of limitations in how HTTP exchanges are mapped onto TCP connections in HTTP/1.1, multiple parallel connections are often used..."

Why don't you just say

  "Because HTTP/1.x does not include a multiplexing layer, multiple
   TCP connections are often used to service requests in parallel.
   However, that has a negative impact on congestion control and network
   efficiency, since TCP does not share congestion control across multiple
   connections."

because those are the actual technical limitations.

....Roy