This message is rather dated (LA IETF), but I haven't seen anything lately on the same topic, nor do there seem to be any relevant RFCs; could anyone perhaps point me to more recent discussions and/or plans to implement the below scheme? Does anyone have projections on when 192/3 will actually be exhausted at the current allocation rate? Does anyone believe the opening of 64/2 (or more likely, a segment thereof) will cause a change in allocation policies or routing filters? Is anyone aware of any problems with current equipment in the major providers that would preclude the deployment of 64/2 CIDR blocks? Has anyone considered the possible effects of IP space being marked "atomic"; that is, not allowed to be sub-allocated to another AS (and therefore hopefully precluding route explosion). Non-atomic allocations could still be made from the 204/6 swamp to support multi-homing for ASes not worthy of a /19 (or whatever the policy is today). Stephen

To: Michael Dillon <michael@memra.com> Subject: Re: Allocation of IP Addresses From: Paul Ferguson <pferguso@cisco.com> Date: Wed, 13 Mar 1996 19:15:44 -0500 Cc: Jim Browning <jfbb@atmnet.net>, "'com-priv list'" <com-priv@psi.com>, "'NANOG List'" <nanog@merit.edu>, "'NIC Registry list'" <nic-registry@internic.net> Sender: owner-nanog@merit.edu

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Well, I knew this topic would come up sooner or later, since it was discussed briefly in LA/IETF at the CIDRD WG meeting(s).

A snippet from the LA/IETF CIDRD minutes:

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Yakov Class A Allocation Guidelines ============================= Motivation Observation 1: 192/3 is 1/8 of the total IPv4 unicast space Observation 2: 64/2 is 1/4 of total IPv4 unicast addrses space Hypothesis1: at some point we will exhaust 192/3 Hypothesis2: at some point we will need to allocate out of 64/2 Observation3: It appears safe to allocate out of 64/2 based on experience documented in RFC???? on Class A Experiment

Recommendation allocation of /17 or larger should be done out of 64/2 allocation of /18 or smaller should be done out of 192/3

Comments? Randy: Do you mean start this now? YR: No, only when we decide it necessary.

Eliot Lear: Can big ISPs get bigger blocks? YR: Yes, it should allow them to. EL: Do we need to advise Registries? EL: Should 192/3 be declared unroutable? YR: Perhaps part of it. BManning: I would like to attach a rider on this. I think before anyone gets anything out of 64/2 that they should agree to give back their old blocks. TonyLi: Is there some reason not to start alloc 64/2 immediately? YR: We don't have to yet, so perhaps we should not. TonyLi: Pressure from international carriers to get large blocks. ELear: We should wait as long as possible to age legacy systems. Tony: There weren't any big problems in the RFC. BManning: Some things were not tested. Only routing protocols were tested. We couldn't figure out a reliable way to test interior routing. We should hold off a little longer before we jump into this. NoelChiappa: We can't get rid of all the legacy systems. Is the cost of hurting the legacy equipment less than the benefit of 64/2.

[general discussion of when we should implement this. Now or wait a little longer for legacy systems to expire.] [discussion of route-able v unroute-able prefixes. Will certain prefix ranges be declared unroute-able in future?] MKosters: @home has a /14 out of net 24, so we have already allocated out of Class A.

BrianC: Suppose IANA decides to do this, and some joe-ISP asks for a /14. We haven't given the Registries any guidance on how to allocate. RConrad: Policy most likely to remain the "power of 2" increase. The size of the ISP is irrelevant with this scheme. Cathy of @home complained that Sean won't take 24/14 only 24/8. Sean Doran raised the issue of charging for prefixes.

Tony advised we leave this for further discussion on the mailing list.

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