[arin-ppml] Update on 2009-3: Global Policy for the Allocationof IPv4 Blocks to RIRs

Stephen Sprunk stephen at sprunk.org
Mon Aug 17 18:08:50 EDT 2009

Scott Leibrand wrote:
> I'm not sure it makes sense to re-write the global policy any more
> than we've already done, but let me see if I can explain the
> possibilities.  As a background point, remember that global policies
> are supposed to define the RIRs' interactions with IANA, while local
> policies define the interactions between RIRs and the organizations in
> their region.
> - RIRs develop their own local policies and procedures  as to
> whether/how they want to reclaim IPv4 space.  If nothing is returned,
> do nothing here.
> - RIRs develop their own local strategies and policies for deciding
> what space goes back to IANA.  If nothing is designated, do nothing
> (until someone complains, and a policy/procedure to return space is
> adopted).
> - RIRs return any such designated space to IANA at quarterly intervals
> in aggregated blocks of /24.
> - IANA creates a returned address space pool.
> - When the IANA free pool is exhausted, and RIRs need more space, they
> can request space from the returned pool.
> - IANA gives out space to requesting RIRs, as defined in this global
> policy.

This makes sense, except that it directly leads to fragmentation across

I oppose any policy that allows an RIR to return space to IANA in any
smaller unit than IANA originally allocated that particular space to an
RIR or directly assigned it to an end-user org (e.g. class B/C legacy
blocks in the "Various Registries" /8s) or does not require IANA to, to
the extent technically feasible, aggregate such returned blocks before
reallocating them to the most logical RIR.

For instance, imagine x.y.0.0/16 is currently APNIC and x.z/16 is
currently RIPE, and the two prefixes could by aggregated into a single
/15; if the former is returned, it should be offered to RIPE first, and
if the latter is returned, it should be offered to APNIC.  Neither
should be allowed to return a fraction of their block but should instead
reuse the remainder -- or encourage the remaining users to renumber out
so that the entire block can be returned.

Frankly, though, I don't see much point in this policy.  When we hit the
wall, everyone is going to be wanting more space and there will be none
in IANA's return pool.  When we finally come to our senses and switch to
IPv6, there will be loads of returns that nobody will want and that the
RIRs might as well hold on to in case of future stupidity in their
region.  Why make extra work for IANA just because one region might be
dumber than the others?  It'd be one thing if we were moving entire /8s,
but mere /24s?  That's nuts.


Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking

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