[e2e] end2end vs smtp

[David P. Reed]

Interesting.
At 12:04 PM 1/25/2002 -0500, Scott Brim wrote:
>On Fri, Jan 25, 2002 04:33:15PM +0000, Lloyd Wood wrote:
> > Is it me, or does point 1 of
> >
> > http://www.ietf.org/IESG/Announcements/draft-bose-smtp-integrity.ann
> >
> > completely neglect the end2end argument?
>
>TCP is end-to-end.

Not at all true.  TCP in the context of email is hop-by-hop.


>The IESG is right.  To the extent that the draft has a point (that TCP's
>checksum limitations are becoming more significant now that people are
>sending huge files in mail), there are better ways to address it, some
>of them already deployed.

The IESG is partly right (point 4) that MIME has the ability to provide 
end-to-end reliability checks.  It does not, however, provide improve 
end-to-end reliability much (even if the user in the loop asks for 
retransmission of the "whole thing" because the 128 bit checksum is 
incorrect, the source may no longer have what was sent).

But Lloyd Wood is right - point 1 is blatantly arguing the exact opposite 
of the end-to-end argument when it says that any reliability requirement 
should be pushed down into the network layers.

We are starting to see the protocol designer equivalent of Gresham's 
law.  Bad designers drive out good ones.  They are cheaper, more prolific, 
and their corrosive effects only become visible in the long term when it's 
too late.  One only has to look at the incredible damage to the 
evolvability of the architecture of the Internet caused by NAT boxes to 
understand why condoning unprincipled garbage designs is a bad strategy.

- David
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