[ppml] Solicing comments: IPv4 to IPv6 Migration Incentive Address Space

Scott Leibrand sleibrand at internap.com
Tue Jun 26 17:13:29 EDT 2007


A couple of critiques of this proposal, which may prevent it from 
gaining consensus:

    * Anyone with an IPv4 assignment from ARIN can request an IPv6
      assignment under existing policy, and they will likely receive it
      with no trouble whatsoever.  (We just requested ours, and it was
      remarkably easy, since we didn't have to justify the size of our
      allocation like we do for IPv4.)
    * While reservation of a /32 is trivial space-wise, reservation of
      that many distinct IPv6 netblocks, with the expectation that they
      can all be routed, will accelerate routing table growth.  To put
      some numbers around the issue, there are some 220,000 routes in
      the IPv4 routing table today, but only some 40,000 ASNs allocated
      (much less actively announcing routes).  Many of those routes come
      from the way RIRs have had to incrementally give out additional
      space as needed, such that announcements cannot be aggregated. 
      (You alluded to this in the case of Verizon, but the problem is
      also present to varying degrees for any small network that has
      grown enough to require additional assignments.)  The current IPv6
      assignment policies resolve this issue by giving networks a much
      larger netblock than they initially need, thereby reducing the
      number of routes that need to be announced in IPv6 to be much
      closer to one per ASN.  If we were to accept announcement of a /56
      for every /24 of IPv4 space, we would give up much of that gain.
    * Many of the benefits you site of algorithmically mapping IPv4
      space into IPv6 space might be compelling if we were planning on
      turning off IPv4 support any time soon.  But since the IPv4
      Internet will continue to function (just stop growing for the most
      part), those benefits seem less compelling.

In short, I'm skeptical that a scheme like this would be helpful, mostly 
because existing IPv6 allocation and assignment policies do a much 
better job than IPv4 policies did of helping constrain routing table 
growth, and also because existing IPv6 policies already make it easy for 
IPv4 holders to get IPv6 space (usually with zero additional cost).

I think we've done most everything we can to make it easy for IPv4 
holders to get IPv6 space.  I think what's needed now is for network 
operators to do the grunt work of actually testing and deploying IPv6 in 
their respective environments.


William Herrin wrote:
> Hi Folks,
> I've prepared a policy proposal I hope to submit to ARIN entitled
> "IPv4 to IPv6 Migration Incentive Address Space." Through preemptively
> assigning IPv6 addresses to IPv4 holders, it seeks to address three
> problems ARIN faces:
> 1. The looming exhaustion of the IPv4 space.
> 2. Obsolete and incorrect legacy IPv4 registration and contact information.
> 3. Legacy IPv4 registrants don't pay their fair share.
> The current draft of the proposal is at:
> http://bill.herrin.us/arin-policy-proposal.html
> If you're willing, please read through it. I'd very much like to hear:
> a. Would you vote Yea or Nay? and b. How would you improve the
> proposal?
> Thanks in advance,
> Bill Herrin
> Note: Resent with from address that's actually subscribed to ppml. If
> the prior one slips through, my apologies for sending it twice.

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