North American Network Operators Group

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Re: Vulnerbilities of Interconnection

  • From: alex
  • Date: Thu Sep 05 14:48:14 2002

> That said, a few years back I wrote the "Interconnection Strategies for 
> ISPs" white paper, which speaks to the economics of peering using exchange 
> points vs. using pt-to-pt circuits. It documents a clear break even point 
> where large capacity circuits (or dark fiber loops) into an IX with fiber 
> cross connects within a building are a better fit (financially) than 
> pt-to-pt circuits.

This obviously would be a thesis of Equinix and other collo space providers,
since this is exactly the service that they provide. It won't, hower, be a
thesis of any major network that either already has a lot of infrastructure
in place or has to be a network that is supposed to survive a physical
attack. 
 
> A couple physical security considerations came out of that research:
> 1) Consider that man holes are not always secured, providing access to 
> metro fiber runs, while there is generally greater security within 
> colocation environments

This is all great, except that the same metro fiber runs are used to get
carriers into the super-secure facility, and, since neither those who
originate information, nor those who ultimately consume the information are
located completely within facility, you still have the same problem.  If we
add to it that the diverse fibers tend to aggregate in the basement of the
building that houses the facility, multiple carriers use the same manholes
for their diverse fiber and so on.

> 2) It is faster to repair physical disruptions at fewer points, leveraging 
> cutovers to alternative providers present in the collocation IX model, as 
> opposed to the Direct Circuit model where provisioning additional 
> capacities to many end points may take days or months.

This again is great in theory, unless you are talking about someone who
is planning on taking out the IX not accidently, but deliberately. To
illustrate this, one just needs to recall the infamous fiber cut in McLean
in 1999 when a backhoe not just cut Worldcom and Level(3) circuits, but
somehow let a cement truck to pour cement into Verizon's manhole that was
used by Level(3) and Worldcom. 

Alex