On Thu, Oct 31, 2013 at 7:24 PM, Matthew Petach <mpetach@netflight.com>wrote:

On Thu, Oct 31, 2013 at 7:02 AM, Ray Soucy <rps@maine.edu> wrote:

...

Was the unplanned L3 DF maintenance that took place on Tuesday a frantic removal of taps? :-)

No need for intrusive techniques such as direct taps:

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=1494884

For shame.... you've sent in a link to some article behind a paywall, with some insane download fee. Which is an equivalent of hand-waving. They must be hiding their content, for fear that flaws be pointed out. "Of all the techniques, the bent fiber tap is the most easily deployed with

minimal risk of damage or detection. The paper quantifies the bend loss required to tap a signal propagating in a single mode fiber"

There will be some wavelengths of light, that may be on the cable, that bending won't get a useful signal from. Bending the cable sufficiently to break the total internal reflection property, and allow light to leak -- will generate power losses in the cable, that can be identified on an OTDR.

Matt

-- -JH

Until you've heard an ex-NSA guy explain to you how this is done, with a device the size of a brief-case, it can seem a little unbelievable. I had that conversation in the late '90s. -----Original Message----- From: Matthew Petach [mailto:mpetach@netflight.com] Sent: Thursday, October 31, 2013 8:27 PM To: Jimmy Hess Cc: NANOG Subject: Re: latest Snowden docs show NSA intercepts all Google and Yahoo DC-to-DC traffic On Thu, Oct 31, 2013 at 5:53 PM, Jimmy Hess <mysidia@gmail.com> wrote:

On Thu, Oct 31, 2013 at 7:24 PM, Matthew Petach <mpetach@netflight.com>wrote:

...

On Thu, Oct 31, 2013 at 7:02 AM, Ray Soucy <rps@maine.edu> wrote:

...

Was the unplanned L3 DF maintenance that took place on Tuesday a frantic removal of taps? :-)

No need for intrusive techniques such as direct taps:

...

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumbe r=1494884

For shame.... you've sent in a link to some article behind a paywall, with some insane download fee. Which is an equivalent of hand-waving.

They must be hiding their content, for fear that flaws be pointed out.

Oy...OK, let me find a document that spells it out a bit more clearly for you.

"Of all the techniques, the bent fiber tap is the most easily deployed with

...

minimal risk of damage or detection. The paper quantifies the bend loss required to tap a signal propagating in a single mode fiber"

There will be some wavelengths of light, that may be on the cable, that bending won't get a useful signal from.

Bending the cable sufficiently to break the total internal reflection property, and allow light to leak -- will generate power losses in the cable, that can be identified on an OTDR.

This patent covers a technique developed to do non-intrusive optical tapping with a 0.5" microbend, with only 0.5dB signal loss: http://www.google.com/patents/CA2576969C Most people aren't going to be able to tell a 0.5dB loss from a microbend tap from a splice job. Matt

...

Matt

-- -JH