RE: stable addressing

["Christian Huitema" <huitema@windows.microsoft.com>]

> No, I don't take my street address when I move, but I do take my
identity
> and identity has been eliminated in IPv6.  That is the problem.

Actually, I know of at least one organization who might very well take
its street address if it moved, as long as it remains within the same
city. Just try to find a street plate numbered "One Microsoft Way"...

The point that Eric made is very real. Renumbering an organization has a
cost. Similarly, using multiple address prefixes inside an organization
has a cost. We may debate how large these costs are, but we cannot
assume that they are null. It is quite clear that these costs grow with
the size of the organization: it is definitely more expensive to
renumber 300,000 computers than 299,999. We may debate whether the cost
increase is sub-linear, linear or super-linear with the size of the
organization, but we cannot deny that everything else being the same, it
is monotonically increasing.

Using a single "portable" address eliminates the renumbering and
multi-addressing costs for the organization, but passes them to the
network. The cost for the network is the cost of maintaining an
additional prefix in the routing tables. In first approximation, this
cost is independent of the size of the organization. 

At that point, we should get a clear picture. Above a certain size, the
cost for the organization is larger than the cost for the network. It
turns out that large organizations are also large customers, which give
them some negotiating power. So, if we just let market forces act their
own way, we can indeed expect that very large organizations will acquire
a single portable prefix.

-- Christian Huitema