Re: "Fragmentation considered harmful"

James M Galvin <galvin@TIS.COM> Wed, 31 January 1990 13:35 UTC

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Reply-To: James M Galvin <galvin@TIS.COM>
To: mogul (Jeffrey Mogul)
Cc: Philippe Prindeville <philipp@gipsy.Gipsi.FR>, MTU Discovery <mtudwg>
Subject: Re: "Fragmentation considered harmful"
In-Reply-To: Your message of Tue, 30 Jan 90 19:20:00 PST. <9001310320.AA20385@acetes.pa.dec.com>
Date: Wed, 31 Jan 90 08:33:43 -0500
Message-Id: <25177.633792823@tis.com>
From: James M Galvin <galvin@TIS.COM>

		Some might argue it is a security breach to let one
		level convey information about (the existance of)
		other levels.  I will leave that to the spooks to
		answer...

	I think you're confusing protocol archictectural layering with
	multi-level security.  Any correctly-implemented multilevel
	security system wouldn't let this information leak out, via
	IPMP or otherwise, if it shouldn't be allowed to leak.

That is one interpretation.  Another is to realize my network may be
"private", and I do not wish to explicitly tell you anything about it,
including its MTU size, regardless of level.

Now I realize that given sufficient trials something like the MTU could
probably be "learned", which is why I said "explicitly" above.  However, I
could also make the learning process hard by going out of my way to confuse
you.

Jim