[ppml] Fwd: Keeping in reserve

[Thomas Narten]

> In general, bisection seems like a good strategy.  The problem with
> bisection from my perspective is what happens when the super-block
> you are assigning from becomes close to "full."

Well, about the time that happens (or well before it, actually!!!), I
would hope/expect that there are periodic reports on how allocations
are going and how the "reserved" space looks. And we'd ask whether the
current "reserve" is doing what is intended and/or whether one needs
to start allocating stuff out of a separate and/or bigger block.

> Because of the IPv6 policy agreed to between IANA & the RIRs.  ARIN
> can't go back and get more IPv6 address space until they have
> assigned/allocated/reserved 50% of the space they have been given.
> At least that is how I read the policy.
> (http://www.icann.org/policies/proposed-ipv6-policy-14jul06.htm)

This policy can presumably be changed, if there is a good reason
to. (And I view this policy as a good first step, but unlikely to be
the perfect policy we will want a few years down the road.)  And if we
were doing sparse allocation, but needed more space in spite of the
current policies, presumably we'd figure out how to change the policy.

We are also a long way off from needing to do this stuff, I suspect,
so we have at least some time to think about it. :-)

The point is though, reserving only a /44 is an arbitrary number, and
one that we may (say 10 or 20 years from now) view as having been a
mistake. It seems prudent not to make these sorts of irreversable
decisions now, if there is no real need to.

Thomas