Hi Fred,
So in the general case I don't see a problem with deprecating
things under the right circumstances, but I do have a problem with
removing them outright. Deprecation doesn't prevent people from using
them, but outright removal can be dangerous. And in this case, the
assertion that one can still use the address prefix in a local manner
is simply incorrect; it can be assigned at the whim of IANA, and
network administrations need to plan accordingly.
Actually, we are being very careful about this in the deprecation
of IPv6 site-local addressing. Christian Huitema and Brian Carpenter
have co-authored a very carefully written deprecation document that
makes it clear how these addresses should be treated to avoid problems
with existing site-local implementations. And, we are planning to
instruct IANA not to return these addresses to the regular allocation
pool.
Margaret