Date: Thu, 07 Feb 2019 23:15:10 +0000 (UTC)
From: Mike Bishop <notifications@github.com>
Reply-To: quicwg/base-drafts
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Message-ID: <quicwg/base-drafts/issues/2430/461627963@github.com>
In-Reply-To: <quicwg/base-drafts/issues/2430@github.com>
References: <quicwg/base-drafts/issues/2430@github.com>
Subject: Re: [quicwg/base-drafts] Reserved versions will "probably" never
 represent a real protocol? (#2430)
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We fear that someone might ossify if they discover that these are *definitely* not real protocol versions.  On the other hand, the thing that breaks is use of these as real protocol versions, which I don't believe we're trying to achieve.  If the middlebox is generating *accurate* VN packets, that seems entirely reasonable (and indistinguishable from actual VN packets).  If they're generating inaccurate VN packets, then our anti-downgrade protections that we've decided to implement RSN will break.

On the other hand, if these ever are real protocol versions, then a junk grease packet using the reserved version will fail to parse as a valid Initial and will just fail rather than eliciting a VN response.

This seems like an impossible battle to win, and a lot of subtlety to expect of middlebox vendors.  Write what we mean and move on.

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<p>We fear that someone might ossify if they discover that these are <em>de=
finitely</em> not real protocol versions.  On the other hand, the thing tha=
t breaks is use of these as real protocol versions, which I don't believe w=
e're trying to achieve.  If the middlebox is generating <em>accurate</em> V=
N packets, that seems entirely reasonable (and indistinguishable from actua=
l VN packets).  If they're generating inaccurate VN packets, then our anti-=
downgrade protections that we've decided to implement RSN will break.</p>
<p>On the other hand, if these ever are real protocol versions, then a junk=
 grease packet using the reserved version will fail to parse as a valid Ini=
tial and will just fail rather than eliciting a VN response.</p>
<p>This seems like an impossible battle to win, and a lot of subtlety to ex=
pect of middlebox vendors.  Write what we mean and move on.</p>

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trying to achieve.  If the middlebox is generating *accurate* VN packets, t=
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otections that we've decided to implement RSN will break.\r\n\r\nOn the oth=
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