[146770] in North American Network Operators' Group
Re: First real-world SCADA attack in US
daemon@ATHENA.MIT.EDU (Jay Ashworth)
Tue Nov 22 10:18:07 2011
Date: Tue, 22 Nov 2011 10:16:56 -0500 (EST)
From: Jay Ashworth <jra@baylink.com>
To: NANOG <nanog@nanog.org>
In-Reply-To: <20111122135956.GA21368@panix.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
----- Original Message -----
> From: "Brett Frankenberger" <rbf+nanog@panix.com>
> The typical implementation in a modern controller is to have a separate
> conflict monitor unit that will detect when conflicting greens (for
> example) are displayed, and trigger a (also separate) flasher unit that
> will cause the signal to display a flashing red in all directions
> (sometimes flashing yellow for one higher volume route).
>
> So the controller would output conflicting greens if it failed or was
> misprogrammed, but the conflict monitor would detect that and restore
> the signal to a safe (albeit flashing, rather than normal operation)
> state.
"... assuming the *conflict monitor* hasn't itself failed."
There, FTFY.
Moron designers.
Cheers,
-- jra
--
Jay R. Ashworth Baylink jra@baylink.com
Designer The Things I Think RFC 2100
Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII
St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274
