Re: Fiber optic vampire taps

[Brad Arlt <arlt () cpsc ucalgary ca>]

On Mon, Dec 23, 2002 at 03:01:19PM -0500, Lee Brink wrote:
> The other method they discussed is to remove the fiber cable's outer 
> insulation and bend it. You could monitor the light signal at the bend 
> via refraction. The two issues they brought up with this method is that 
> AFATK it's only a theoretical method, and with the refraction a severe 
> loss of db would result and be immediately noticed.
>
> I personally don't know much about fiber optic cabling, but the
> people in the network department that do know were confident on the
> above info.

I have heard similar.  The insulation is pried back, and the glass is
then shaved and *really* polished.  There is no need to bend multimode
fibre, as the light is already reflecting heavily, and you should only
have to bend single mode very slightly.  There is substantial signal
lose, but if one does it right, the amount of signal arriving at each
end is still sufficient to maintain data transfer and link status.

I have not seen this done in person, but I have heard some "a friend
of a friend" stories.

-----------------------------------------------------------------------
   __o          Bradley Arlt                    Security Team Lead
 _ \<_          arlt () cpsc ucalgary ca                University Of Calgary
(_)/(_)         I should be biking right now.   Computer Science