tapping undersea fibers?

Peter Fairbrother peter.fairbrother at ntlworld.com
Mon Jun 4 17:10:17 EDT 2001

> John Denker at jsd at research.att.com wrote:

> I wrote:
>>> AfricaONE has a backbone that circles the continent offshore, plus
>>> separate drops for each country, when it would have been vastly cheaper
>>> to go by land....[Offshore is] less likely to be tapped by hostile powers.
> At 12:38 AM 6/4/01 -0400, Lenny Foner wrote:
>> My understanding of this, which could very well be wrong, was not
>> concern about tapping, but concern over damage.
> Well, of course there is concern about all sorts of threats:
> *) Tapping
> *) Damage
> -- inadvertent
> -- otherwise
> But let's ask what are the costs and benefits of various options:
> 1) One obvious option is to build a _ring_ of fiber on dry land.
> 1a) Sure, there will be an inadvertent cut now and then (due to some
> klutz with a backhoe) but such cuts can be repaired.  The cost of repairs
> is infinitesimal compared to the cost of running the cable
> offshore.  Because it is a ring, customers won't notice cuts if they happen
> one at a time (and are repaired promptly);

Prompt repairs (in another country) in Africa? Guaranteed? don't make me
laugh. And when the cable might go through four war zones in an average
year? don't make me cry. Such a cable might last six weeks before becoming
permanently unuseable.

> it would take _two_ cuts to
> cause a partition.

If a backhoe can do it, there will be _lots_ of cuts.

> 1b) There will be wars now and then.  Each combatant _will_ want to cut
> the adversary's cable.  (Ever hear of a foreign minister named
> Zimmerman?)  There's not a lot that the cable operator can do to maintain
> service in the war zone.  But remember it takes two cuts, including one
> _not_ in the war zone, before anybody outside the war zone is left in the
> dark.

Alliances, anyone? 

Perhaps one country says "We want to know everything that's in the cable, or
it doesn't get through, and by the way you have to pay taxes on through
traffic"? Then the other loop segment is vulnerable.

Or in a war,  a country that's in the surviving loop says "Oops, sorry, we
have an accidental cut. We'll get it repaired soon, sooner perhaps if

Or terrorists/mercenaries/country A's army cut it in country C.

Anyone can cut that cable, at any time, and cause disturbances.

> 1c) It is not impossible to have damage (inadvertent or otherwise) to
> an offshore cable, as Herr Zimmerman found out.

Sure, so what? That's why they want it _far_ offshore, it's safer from

> 1d) A dry-land configuration would provide !much! more functionality --
> more places for paying customers to connect.

A local spur cable can do the same thing at much the same cost. And all
those taps are a security nightmare...

> 2) You can do even better if build something more like a mesh than a
> simple ring.  Such a structure would be tremendously robust against damage,
> and would provide even more places for customers to connect.

It would cost a lot more. It would need so many treaties that it would never
get agreed. People at mesh points could trap traffic from/to a specific
country. As the individual cables have, for geographical reasons, to go
through, in some cases, a maximum of two countries, there is no benefit in a
mesh against DoS if both those countries are against through traffic.

> So it seems to me that the principal rationale for putting the cable
> offshore is the expectation that the two-bit warlord next door would have a
> hard time tapping the backbone.

Not to me. If you want to avoid tapping, use end-to-end encryption.

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