[ppml] geo addressing

[Michael.Dillon at btradianz.com]

> as of today we don't have a
> routing infrastructure and/or the necessary protocols to make geo
> addressing work. Sorry to rain on the parade but this is flogging a dead
> horse; we have explored these ideas years ago with no success.

I disagree on several points. First of all, geotopological addressing
is not the same thing as was discussed in the past. We do have the 
necessary protocols to make geo-topological addressing work because 
it uses all the same protocols that we have today without any protocol
changes. It even does multihoming in exactly the same way using BGP 
and it aggregates prefixes in the same way that ISPs do so today.

Geotopological addressing only requires the RIRs to set aside one
of the remaining 7 regions of IPv6 space for geo-topological addressing
and to start handing out allocations consistent with the geotopology.
This geotopology is based partly on geography but still considers
topology to be important.

The highest level cut is made based on continents just like 
the RIRs today. This is geography and it is also topology 
because intercontinental traffic is expensive and must transit 
limited intercontinental fibers. At the lowest level, we have 
the city, which has a population of 100,000 or greater. 
The city serves as an economic and communications hub for
its surrounding area which often spans national borders. 

Then, in between these two is a middle layer of aggregation 
for a cluster of cities which tend to communicate more with 
each other than with other cities on the same continent. In 
some areas this will be easy to determine, for example Australia,
New Zealand, and Papua/New Guinea would make a logical cluster in
the APNIC region. But in some other regions, such as ARIN's
region it is less clear. That's OK because this mid level of aggregation
is not about borders, it is about where we can cluster some cities in
order to aggregate their routing detail under a covering prefix.
It might mean that people in Denver and Salt-Lake City send all
their Detroit traffic to Chicago because Detroit and Chicago are
hidden inside the same covering prefix.

This is not a bad thing in general. But remember, there are no
rules about how this is done. If your company has networks in 
all those cities, and you have circuits direct from Denver to 
Detroit, then you are free to keep as much unaggregated detail
as you want in your routing tables.

This doesn't solve the IPv6 multihoming problem in general.
It specifically addresses the long tail multihoming problem.
This is the large number of small ISPs and small to mid-size
companies for whom the Internet is mission critical and who
want to multihome in order to enhance their network resiliency.

And geotopological addressing is entirely optional. It only
impacts the people who want to use it.

--Michael Dillon