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Re: [tsvwg] Alternative version of the UDP FRAG option

"C. M. Heard" <heard@pobox.com> Wed, 13 March 2019 05:14 UTC

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From: "C. M. Heard" <heard@pobox.com>
Date: Tue, 12 Mar 2019 22:14:10 -0700
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To: Joe Touch <touch@strayalpha.com>
Cc: Gorry Fairhurst <gorry@erg.abdn.ac.uk>, tsvwg <tsvwg@ietf.org>
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Subject: Re: [tsvwg] Alternative version of the UDP FRAG option
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On Tue, Mar 12, 2019 at 9:48 PM Joe Touch <touch@strayalpha.com> wrote:
> > On Mar 12, 2019, at 9:36 PM, C. M. Heard <heard@pobox.com> wrote:
> >
> > Having the revised OCS cover the data in each fragment provides protection
> > that is essentially equivalent to that provided by the post-reassembly checksum
> > proposed in the current draft.
>
> The composition of checksums is not equivalent to a checksum. It does not offer
> equivalent protection, esp. in errors within the reassembly process itself.

The equivalence is a mathematical one, assertions to the contrary
notwithstanding.

Heard

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