On Sunday, April 27, 2003, at 05:21 PM, Margaret Wasserman wrote:
As John Klensin pointed out on this same list several weeks ago
(and I'm sure he said it better than I will), the decision to
use ambiguous local addressing in IPv4 (i.e. RFC 1918 addresses)
was partially motivated by the desire to conserve IPv4 address
Yes. Of course, there were and are other reasons, the most significant
of which is in conjunction with the use of NAT to provide some level of
provider independence (both in terms of avoiding the necessity to
renumber when changing providers as well as not having to "purchase"
additional IP addresses from the service provider).
In IPv6, we don't have an address space shortage, so there
is no reason to introduce architectural complexity to conserve
While it is true that address conservation isn't that significant an
issue, the whole issue of provider independence (or lack thereof)
continues to exist.
Continuing to ignore this fundamental requirement on the part of
enterprise network operators is getting us no where. It certainly
isn't getting us to IPv6 deployment.