[ppml] geo addressing

Michael.Dillon at btradianz.com Michael.Dillon at btradianz.com
Tue Nov 22 05:12:32 EST 2005

> what makes you think network topology is static enough that
> this temporary optimization won't cost more in the long term
> than it buys in the short term?

Because I believe that it is unlikely that many new cities will
form causing nearby cities to shrink. Therefore the topology of
cities and their interconnects will remain roughly as is. Of course
the bandwidth of fibre between cities will increase at varying
rates, but I don't foresee major shifts in the economy such as 
the fall of the Roman empire or the conquest of North America.

In addition, I have seen no evidence to show that it is common
for organizations to move their networks from one city to another.
Most of the topology churn happens inside a metro area. The
geotopological address model allows for this churn but hides it
from the global (and regional) routing system.

Past evidence from companies going into bankruptcy, merger,
or acquisition, shows that companies tend to integrate New
York routers within New York and LA routers within LA. In other
words, you do get PoP consolidation and merger of network resources
within a city more often than people move those resources to 
another city.

When I am talking about topology, I am not talking about every last
detail of every last router and circuit. It fits ISPs with one
PoP in a city, ISPs with 5 PoPs in a city and ISPs with no PoPs
but some metro ring topology with edge routers scattered
in customer buildings. In all cases, there is a city that has
circuits running to other cities. At that level, the topology
does not change as much.

> # The network topology of today now roughly matches the topology
> # of transportation systems and economic flows.  In other words
> # the nodes in the network are cities or metropolitan areas.
> ok, so restating my question so we can both be sure i asked it:
> what relationship does the network topology of today have to the
> network topology of tomorrow, and why, and how do you know?

Networks serve people. People live in cities. Therefore the network
topology of tommorrow *MUST* connect cities together. Inside the
city, people and organizations constantly shift and move. Therefore
the topology in the city will constantly be changing. This change 
does not need to be visible to other cities.

By selecting cities larger than 100,000 to be centers of aggregation
we allow for areas which could see considerable population growth.
Such growth tends to add to existing cities rather than create new 
ones. I do not suggest that city address allocation size should be
based on current population. I would like to see it based on future
population as determined by economists, statisticians, geographers 
who understand the limits to growth in order to make realistic 

And if we get it a little bit wrong this is good. It would be very
bad if we solved all the problems of the world for future generations
because then they would be bored out of their minds with no real
problems to solve for themselves. So I'm not looking for perfection

--Michael Dillon

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