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v4 exhaustion and v6 impact [Re: cost of dual-stack vs v6-only]

  • From: Pekka Savola
  • Date: Thu Mar 13 12:55:06 2008

I changed the subject line.

On Thu, 13 Mar 2008, Leo Bicknell wrote:
My point is that it seems somewhat premature to talk extensively of 2)
-> 3) transition because we haven't even figured out 1) -> 2) yet.
Getting to 2) is the challenge, from there it is straightforward.

The driver for 1-2 is the end of the IPv4 free pool. It doesn't much matter if the cause is IPv4 simply not being available anymore, or if the result is some way of moving IPv4 addresses around for money; they both will get the bean counters attention real quick. In essense the cost of IPv4 is going to dramatically rise, one way or another.

And that's only the first order effect of getting the addresses.
Second order effects like hanling the routing table deaggregation
haven't begun to be calculated.

Many people seem to have waken up from the slumber lately with a realization that when IANA/RIR v4 pool runs out in a couple of years, v6 had better be ready for prime time!

While the goal may be good, a reality check might be in order. AFAICS, the impact will be that residential and similar usage will be more heavily NATted. Enterprises need to pay higher cost per public v4 address. IPv4 multihoming practises will evolve (e.g., instead of multihoming with PI, you multihome with one provider's PA space; you use multiconnecting to one ISP instead of multihoming). Newcomers to market (whether ISPs or those sites which wish to start multihoming) are facing higher costs (the latter of which is also a good thing). Obviously DFZ deaggregation will increase but we still don't end up routing /32's globally.

While price for a /20 or /16 of address space might go up pretty high, a /24 can still be obtained with a reasonable cost. Those ISPs with lots of spare or freeable v4 space will be best placed to profit from new customers and as a result v6 will remain an unattractive choice for end-users.

IANA and RIRs running out of v4 space may allow making a better case to an ISP's management that their backbone should be made v6 capable (to support customers who want v6) but it doesn't provide the case for the ISP to deploy v6 to its residential users, and it doesn't provide a case for the enterprises to start v6 transition (because they need to support v4 anyway). It may also make a case for ISPs which don't have much spare IPv4 space and cannot free or obtain it to try to market v6 to their end-users.

So v6 capabilities in the ISP backbones will improve but the end-users and sites still don't get v6 ubiquituously. This is a significant improvement from v6 perspective but is still not enough to get to 90% global v6 deployment.

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings