proposal for RIPE's IPv6-address space structure

  > Frank Hoffmeister <Frank.Hoffmeister at Germany.EU.net> writes:
  > 
  > In fact, we are looking for a scalable and efficient (exterior) routing
  > scheme. 

Right. 

  > Given that in the future there will be MANY ISPs worldwide
  > the vast amount of associations of provider-based prefixes to ASes
  > might impose a problem to the size of the routing tables.

Yes it might.  On the other hand I am not totally pessimistic.  Router
vendors are getting things right by doing away with forwarding table
caching, allowing reasonable sizes of forwarding tables in backbone type
routers and fully separating routing computations form forwarding.  The
probnlem is that we are still engineering very much to a moving target. 
If anyone can forecast the development curve of

	- number and size of ISPs
	- interconnectivity model of ISPs
	- number and size of customers
	- connectiviy trends of customers (multi/single homed etc)
	- router capabilities
	- exterior routing technology

it is easy to engineer address space allocation and assignment
procedures that produce good or even optimal results.  Unfortunately
there is no consensus about these developments and the more wise people
do not even try to speculate.  Therefore I would like to keep options
open as long as possible and also use a scheme with lots of flexibility.
It is more tractable to devise procedures that work for the immediate
future but they need to be flexible to be adapted to a changing
environment.  The Internet community and especially the providers and
the registries have had great successes with that.  Consider the
registration schemes in place 4 years ago.  Consider the time frame it
took to devise and effectively deploy CIDR.  We are good at this. 

  > So, there is some need to aggregate routes to providers.
  > Having regional prefixes is one option.

I would like to hear what you mean by 'regional prefix'. How is it defined?
How does it relate to netowrk topology?  How does aggregation to it work? 


Daniel