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RE: Benjamin Kaduk's Discuss on draft-ietf-httpbis-http2bis-06: (with DISCUSS and COMMENT)

From: Mike Bishop <mbishop@evequefou.be>
Date: Sun, 9 Jan 2022 06:44:13 +0000
To: Martin Thomson <mt@lowentropy.net>, Benjamin Kaduk <kaduk@mit.edu>, The IESG <iesg@ietf.org>
CC: "draft-ietf-httpbis-http2bis@ietf.org" <draft-ietf-httpbis-http2bis@ietf.org>, "httpbis-chairs@ietf.org" <httpbis-chairs@ietf.org>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>, Mark Nottingham <mnot@mnot.net>
Message-ID: <BLAPR22MB2259E5916F4D47743CB80EC6DA4F9@BLAPR22MB2259.namprd22.prod.outlook.com>
I don't think I was mentioned three times, but I shall consider myself summoned nonetheless.

The H3 text is:

Clients SHOULD NOT open more than one HTTP/3 connection to a given IP address and UDP port, where the IP address and port might be derived from a URI, a selected alternative service ([ALTSVC]), a configured proxy, or name resolution of any of these. A client MAY open multiple HTTP/3 connections to the same IP address and UDP port using different transport or TLS configurations but SHOULD avoid creating multiple connections with the same configuration.

The HTTP/3 text does allow for differences of TLS configurations, which would encompass different certificates and/or SNI values, so I don’t think there’s necessarily a conflict here.

The H3 text was written in contemplation of Alt-Svc being the primary means of finding the endpoint and the Alt-Svc entries potentially covering a different set of hosts than the endpoint has certificates for.  By keying on IP address, it means that two Alt-Svc advertisements pointing to different hostnames which resolve to the same IP address would still enable connection reuse if the certificate covers both origins, while the HTTP/2 text would advise separate connections to that IP address for the two origins.

I think we could leave the text as-is in both documents and be fine.  I think we could normalize the documents to either version and be fine.  I tend to prefer more coalescing than less, FWIW.

-----Original Message-----
From: Martin Thomson <mt@lowentropy.net>
Sent: Friday, January 7, 2022 9:44 AM
To: Benjamin Kaduk <kaduk@mit.edu>; The IESG <iesg@ietf.org>
Cc: draft-ietf-httpbis-http2bis@ietf.org; httpbis-chairs@ietf.org; ietf-http-wg@w3.org; Mark Nottingham <mnot@mnot.net>
Subject: Re: Benjamin Kaduk's Discuss on draft-ietf-httpbis-http2bis-06: (with DISCUSS and COMMENT)

> Section 9.1


>    Clients SHOULD NOT open more than one HTTP/2 connection to a given

>    host and port pair, where the host is derived from a URI, a selected

>    alternative service [ALT-SVC], or a configured proxy.


> quic-http has similar text (in §3.3), but it refers to a given IP

> address and port, rather than host and port.  Is the difference

> between host and IP address significant when comparing h/2 and h/3?

> (When using IP addresses, we of course have to additionally talk about

> name resolution of the other types of identifier.)

I honestly don't know.  I think perhaps host is better in this case in the sense that clients aim to connect to hosts and connection coalescing is not a requirement, just permitted (as noted in the text that follows).  I'm not sure that it really matters ultimately, but it's worth checking.

Perhaps Mike Bishop can help us here.
Received on Sunday, 9 January 2022 06:44:30 UTC

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