Hierarchy, Force Monopoly, and Geodesic Societies

[Jim Dixon]

On Fri, 9 Apr 2004, Eugen Leitl wrote:

> Internet is mostly a tree (if you look at the connectivity maps).

Not at all.  A tree has a root; the Internet doesn't have one.  Instead
you have several thousand autonomous systems interconnecting at a large
number of peering points.

>                                                               Wires over
> long distances will tend to follow geodesics (because cables are expensive,
> and an enterprise will try to minimize the costs).

For a long time, most traffic between European countries was routed
through Virginia.  This has improved only in the last few years.  In
the same way a lot of Pacific traffic still runs through California.
In each case what matters is not geography but politics and quixotic
regulations.

Within most countries the same sort of illogic applies.  In the UK, for
example, most IP traffic flows through London, and within London most IP
traffic flows through the Docklands area, a geographically small region of
East London.  It's fractal: even within Docklands, almost all traffic
flows through a handful of buildings, and there is a strong tendency for
most of that inter-building traffic to pass through a very small number of
ducts.

>                                                   Current flow is mostly
> dictated by frozen chance, politics (peering arrangements). Automating
> peering arrangments and using agoric load levelling in the infrastructure
> will tend to erode that over time. Over time, physical lines will tend to be
> densest along densest traffic flow.

Very true -- but this has nothing to do with geodesics.

> American cities are orthogonal, European usually radial. The cities are

? City layouts that I am familiar with are either haphazard or built
around rings or some mixture of the two.  MFS built a US national ring,
a ring in New York City, a ring in London, and rings elsewhere in Europe.
Other carriers tended to follow the same pattern.

> connected with traffic ducts (rail, highway) which is typically loosely
> geodesic (but for obstacles in the landscape). Fiber typically follows
> railway or highway.

That's certainly true, but now you are talking about political decisions
made ages ago.  Many roads in England were built by the Romans.  These
roads lead to London.  You see the same pattern on the Continent, of
course, with the roads leading to the local capital (Paris, say) and then
on to Rome.  That is, fiber optic paths today reflect the strategic
requirements of the Roman Empire, not geometry.

--
Jim Dixon  jdd at dixons.org   tel +44 117 982 0786  mobile +44 797 373 7881
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