Address clustering intuition

No, this does not work. Looking at Europe, I know of several ISPs
to which the shortest path from here (Amsterdam, the Netherlands)
is via MAE-EAST; they either don't have external connectivity
on the continent itself, or we have no provider willing to provide
transit between here and their continental connectivity.

It would seem that given a free market these providers would find it
cheaper to connect locally than make two hops across the Atlantic. Even
if a few go the long way, I would think cost considerations would keep
the number of such providers down, and limit them to the East Coast of
the US. This would accomplish the same effect of limiting the number
of routers that would need to know this detail

There is a second, similar reason: assume that A and B each operate
in the same area. They use different carriers for transit to MAE-EAST.
Who of these is going to announce the aggregated announcement?
If A does it, it pays for the transit for customers of B.
If they both announce it, then they still pay for eachother's

Presumably MAE-EAST would know enough detail about who was connected to
A and B to make the right decision on transit carrier. If A and B were
far enough away from MAE-EAST then they would probably find it more
economic to make an interchange locally.

PS: it seems that a FAQ on this is desired (CIDRisation, router capacity
growth vs routing table growth, flaps, need to renumber, etc), basically
the topic of various discussions on NANOG, CIDRD, and probably
other places. Volunteers?

I'll volunteer to read it :slight_smile:

-- Walt