North American Network Operators Group

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

  • From: Owen DeLong
  • Date: Thu Mar 13 13:21:33 2008

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.

I am confused by your statement. It appears you are saying that it is a good
thing for sites that wish to multihome to face higher costs. If that is truly
what you are saying, then, I must strenuously disagree. I think that increased
cost for resilient networking is a very bad thing.

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.

Only for some limited period of time. Even those "freeable" /24s will get
used up fairly quickly.

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.

The case for IPv6 end-user deployment will most likely occur when new
IPv4 addresses for those customers become more costly than supporting
a NAT-PT infrastructure with the appropriate DNS hackery and such.

It would be nice (and cheaper in the long run) if ISPs were ahead of that
curve in some way, but, the reality is that's probably going to be the driver.
Eventually, enough NAT-PT eyeballs will drive IPv6 native content
capabilities (although in ability to get IPv4 addresses for new content
hosts may also serve as a driver there).

In terms of enterprise, I think that will be the last group to convert.
I don't think you will see much enterprise level migration until they
are faced with their ISPs wanting to shut down IPv4 and raising the
IPv4 transit costs accordingly.  However, once we reach somewhat
minimal critical mass in IPv6 content, and, NAT-PT solutions are
more readily available and better understood, I think you'll see
most new enterprise deployments being done with IPv6.

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.

I'm not sure why 90% is necessary or even desirable in the short
term.  What's magic about 90%?  What I think is more interesting
is arriving at the point where you can deploy a new site entirely
with IPv6 without concerns about being disconnected from some
(significant) portion of the internet (intarweb?).

Once we're at that point, the rest can sort itself as the timeframe
becomes merely an issue of economics.  Prior to that point, the
issues are of much greater potential impact beyond the mere