Re: [GLOBAL-V6] New draft available: IPv6 Address Allocation andAssignment Global Policy

[Steve Deering <deering@cisco.com>]

At 9:28 AM +0100 2/7/02, Gert Doering wrote:
>different from IPv4, "renumbering [in IPv6] is easy" (supposedly)...

No, no, no, no, no.  IPv6 has some features to make renumbering easiER,
but it still may not be easy for some or even many sites, due to the
many ways and places in which IP addresses are used (for most of which
we do *not* have automated means of renumbering).  Please do not adopt
policies that assumes renumbering will be entirely painless for end
customers, let alone for ISPs.  Among the conflicting demands of
conservation, aggregation, availability, etc. should be included
"stability", where a "stable" address assignment is not a permanent-
for-life assignment, but rather one that ought to be good for at least
a couple of years in most cases, and one that ought not to be changed
for less-than-compelling reasons.

And on the general topic of discussion, I agree with Thomas.  Unless
and until we figure out how to do globally flat routing, it is vital
to ensure aggregatability to a reasonable number of prefixes.  I
understand and appreciate the difficulty of defining "who's an ISP",
and especially "who's a top-level ISP"; the RIR's "slow start" approach
seems like the least bad scheme that anyone has yet been able to come
up with, despite its flaws, so I'm surprised to see it discarded --
for IPv6 (if that's what's happening).  I do wish we could converge
on one of the possible multihoming solutions that would reduce the
pressure for multihomed sites to seek PI prefixes...

As for the research nets serving 50 universities, I don't think they
should get /32s.  If they were instead given longer prefixes and if,
at some point in the future we end up with so many such longer prefixes
that ISPs are forced to filter some of them out, the (presumably)
relatively small number of especially "worthy" long-prefixes could
be granted exceptions in the filter rules without too much operational
effort (the real effort being the political one of identifying the
worthies).

The HD Ratio calculations that have been used to justify the current
address field partitioning assume that the high-order /48 is being
carefully managed, not squandered, so non-extravagance is still
required at that level (i.e., something more generous than
"conservation" but less generous than just giving huge blocks of /48s
to anyone who asks).

Steve

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